RFC: Reference updater filesystem
There has been interest in an image based software updater in Yocto Project. The proposed solution for a image based updater is to use Stefano Babic's software updater (http://sbabic.github.io/swupdate). This software do a binary copy, so it is needed to have at least two partitions, these partitions would be the rootfs and the maintenance partition. The rootfs it's the main partition used to boot during the normal device operation, on the other hand, the maintenance will be used to update the main partition.
To update the system, the user has to connect to device and boot in the maintenance partition; once in the maintenance partition the software updater will copy the new image in the rootfs partition. A final reboot into the rootfs it is necessary to complete the upgrade.
As mentioned before the the software will copy an image to the partition, so everything in that partition will be wiped out, including custom configurations. To avoid the loss of configuration I explore three different solutions:
1. Use a separate partition for the configuration.
a. The pro of this method is the partition is not touched during the
update.
b. The con of this method is the configuration is not directly in
rootfs (example: /etc).
2. Do the backup during the update.
a. The pro is the configuration is directly in rootfs.
b. The con is If the update fail most likely the configuration would
be lost.
3. Have an OverlayFS for the rootfs or the partition that have the configuration. a. The pro is the configuration is "directly" in rootfs.
b. The con is there is need to provide a custom init to guarantee the
Overlay is mounted before the boot process.
With the above information I'm proposing to use a separate partition for the configuration; this is because is more reliable and doesn't require big changes in the current architecture.
So, the idea is to have 4 partitions in the media:
1. boot. This is the usual boot partition
2. data. This will hold the configuration files. Not modified by updates.
3. maintenance. This partition will be used to update rootfs.
4. rootfs. Partition used for normal operation.
Mariano
Quoted 1 line · Mariano Lopez
There has been interest in an image based software updater in Yocto Project.
Ok. Sure, it might be nice with something that can be shared, instead off everyone's building our own solutions.
Quoted 6 lines
The proposed solution for a image based updater is to use Stefano Babic's software updater (http://sbabic.github.io/swupdate). This software do a binary copy, so it is needed to have at least two partitions, these partitions would be the rootfs and the maintenance partition. The rootfs it's the main partition used to boot during the normal device operation, on the other hand, the maintenance will be used to update the main partition.
I haven't checked the swupdate tool, though I'd suspect that it also supports the alternating rootfs use case? (I.e. run system1 update system2; reboot to system2. Next update is system1). This is a rather common setup, not least when you need a remote upgrade facility.
Would your proposed inclusion to the Yocto Project support that case too?
Quoted 4 lines
To update the system, the user has to connect to device and boot in the maintenance partition; once in the maintenance partition the software updater will copy the new image in the rootfs partition. A final reboot into the rootfs it is necessary to complete the upgrade.
Like said above, not all system can be reached manually (at least not in cost efficient way). Sure, the mainenance partition scheme can be made to work anyway...
Quoted 9 lines
As mentioned before the the software will copy an image to the partition, so everything in that partition will be wiped out, including custom configurations. To avoid the loss of configuration I explore three different solutions:
1. Use a separate partition for the configuration.
a. The pro of this method is the partition is not touched during the
update.
b. The con of this method is the configuration is not directly in rootfs
(example: /etc).
I'd vote for that as well. Though, I only keep the re-writable configurations here. The one that are constant between all systems are shipped in /etc in the read-only-rootfs.
Quoted 9 lines
With the above information I'm proposing to use a separate partition for the configuration; this is because is more reliable and doesn't require big changes in the current architecture.
So, the idea is to have 4 partitions in the media:
1. boot. This is the usual boot partition
2. data. This will hold the configuration files. Not modified by updates.
3. maintenance. This partition will be used to update rootfs.
4. rootfs. Partition used for normal operation.
How flexible to you intend to make this system? Allow everything that swupdate supports? Or a specific subset?
Cheers,
Anders
Signature · 2 lines
Anders Darander, Senior System Architect ChargeStorm AB / eStorm AB
Quoted 5 lines · Anders Darander
Quoted 1 line · Mariano Lopez
There has been interest in an image based software updater in Yocto Project.
Ok. Sure, it might be nice with something that can be shared, instead off everyone's building our own solutions.
The idea is to integrate one, not build one from the scratch.
Quoted 7 lines
Quoted 7 lines
The proposed solution for a image based updater is to use Stefano Babic's software updater (http://sbabic.github.io/swupdate). This software do a binary copy, so it is needed to have at least two partitions, these partitions would be the rootfs and the maintenance partition. The rootfs it's the main partition used to boot during the normal device operation, on the other hand, the maintenance will be used to update the main partition.
Quoted 7 lines
I haven't checked the swupdate tool, though I'd suspect that it also supports the alternating rootfs use case? (I.e. run system1 update system2; reboot to system2. Next update is system1). This is a rather common setup, not least when you need a remote upgrade facility.
Would your proposed inclusion to the Yocto Project support that case too?
Yeah, it would be possible to have two "rootfs" and do the update and the just reboot one time.
Quoted 8 lines
Quoted 5 lines
To update the system, the user has to connect to device and boot in the maintenance partition; once in the maintenance partition the software updater will copy the new image in the rootfs partition. A final reboot into the rootfs it is necessary to complete the upgrade.
Like said above, not all system can be reached manually (at least not in cost efficient way). Sure, the mainenance partition scheme can be made to work anyway...
I plan to release this in phases, in the first one it will be manually do the update. The idea is implement tools to automate the process of the update (where it can be automated).
Quoted 22 lines
Quoted 10 lines
As mentioned before the the software will copy an image to the partition, so everything in that partition will be wiped out, including custom configurations. To avoid the loss of configuration I explore three different solutions:
1. Use a separate partition for the configuration.
a. The pro of this method is the partition is not touched during the
update.
b. The con of this method is the configuration is not directly in rootfs
(example: /etc).I'd vote for that as well. Though, I only keep the re-writable configurations here. The one that are constant between all systems are shipped in /etc in the read-only-rootfs.
Quoted 8 lines
With the above information I'm proposing to use a separate partition for the configuration; this is because is more reliable and doesn't require big changes in the current architecture.
So, the idea is to have 4 partitions in the media:
1. boot. This is the usual boot partition
2. data. This will hold the configuration files. Not modified by updates.
3. maintenance. This partition will be used to update rootfs.
4. rootfs. Partition used for normal operation.
Quoted 2 lines
How flexible to you intend to make this system? Allow everything that swupdate supports? Or a specific subset?
If you are referring to the filesystem creation I would say very flexible. It will be implemented using wic instead of a class, so just needs to change a file to suit your needs. If you refer to the swupdate features, I plan to have a generic use case; as an example I won't use the MTD capabilities of the software.
Quoted 4 lines
Cheers,
Anders
Quoted 24 lines · Mariano Lopez
There has been interest in an image based software updater in Yocto Project. The proposed solution for a image based updater is to use Stefano Babic's software updater (http://sbabic.github.io/swupdate). This software do a binary copy, so it is needed to have at least two partitions, these partitions would be the rootfs and the maintenance partition. The rootfs it's the main partition used to boot during the normal device operation, on the other hand, the maintenance will be used to update the main partition.
To update the system, the user has to connect to device and boot in the maintenance partition; once in the maintenance partition the software updater will copy the new image in the rootfs partition. A final reboot into the rootfs it is necessary to complete the upgrade.
As mentioned before the the software will copy an image to the partition, so everything in that partition will be wiped out, including custom configurations. To avoid the loss of configuration I explore three different solutions:
1. Use a separate partition for the configuration.
a. The pro of this method is the partition is not touched during the
update.
b. The con of this method is the configuration is not directly in rootfs
(example: /etc).
Quoted 1 line
Configuration files can be anywhere a package decides to install them. So
having a single partition would be difficult. If you could, you would most likely be forced to have an initramfs to make sure /etc was mounted before init runs.
Quoted 6 lines
2. Do the backup during the update.
a. The pro is the configuration is directly in rootfs.
b. The con is If the update fail most likely the configuration would be
lost.Why would the configuration be lost if the update fails? Couldn't it just
be stored on the thumbdrive?
Quoted 23 lines
3. Have an OverlayFS for the rootfs or the partition that have the configuration.
a. The pro is the configuration is "directly" in rootfs. b. The con is there is need to provide a custom init to guarantee the
Overlay is mounted before the boot process.With the above information I'm proposing to use a separate partition for the configuration; this is because is more reliable and doesn't require big changes in the current architecture.
So, the idea is to have 4 partitions in the media:
1. boot. This is the usual boot partition
2. data. This will hold the configuration files. Not modified by updates.
3. maintenance. This partition will be used to update rootfs.
4. rootfs. Partition used for normal operation.Mariano
--
_______________________________________________
Openembedded-core mailing list
[email protected]
http://lists.openembedded.org/mailman/listinfo/openembedded-core
Quoted 30 lines · Randy Witt
On Mon, Nov 23, 2015 at 1:41 PM, Mariano Lopez <[email protected] <mailto:[email protected]>> wrote:
There has been interest in an image based software updater in Yocto Project. The proposed solution for a image based updater is to use Stefano Babic's software updater
(http://sbabic.github.io/swupdate). This software do a binary copy, so it is needed to have at least two partitions, these partitions would be the rootfs and the maintenance partition. The rootfs it's the main partition used to boot during the normal device operation, on the other hand, the maintenance will be used to update the main partition.To update the system, the user has to connect to device and boot in the maintenance partition; once in the maintenance partition the software updater will copy the new image in the rootfs partition. A final reboot into the rootfs it is necessary to complete the upgrade.
As mentioned before the the software will copy an image to the partition, so everything in that partition will be wiped out, including custom configurations. To avoid the loss of configuration I explore three different solutions:
1. Use a separate partition for the configuration.
a. The pro of this method is the partition is not touched during
the update.
b. The con of this method is the configuration is not directly
in rootfs (example: /etc).
Quoted 1 line
Configuration files can be anywhere a package decides to install them. So having a single partition would be difficult. If you could, you would most likely be forced to have an initramfs to make sure /etc was mounted before init runs.
/etc was an example, the image should have the required files to make the target boot and the get the application configuration from this other partition. This is like openwrt does, it has a read-only rootfs and small read-write partition where the user can write its configuration and restore it at boot time.
Quoted 6 lines
2. Do the backup during the update.
a. The pro is the configuration is directly in rootfs. b. The con is If the update fail most likely the configuration
would be lost.Why would the configuration be lost if the update fails? Couldn't it just be stored on the thumbdrive?
If there is a power loss while the configuration is copied, the partition could go corrupt and would be difficult to recover. And as you mentioned before the configuration files could be anywhere, so the script must be customized to get all those files and once the update is complete another script must restore those files, these could be cumbersome instead of the application have the config in another partition.
Quoted 26 lines
3. Have an OverlayFS for the rootfs or the partition that have the configuration.
a. The pro is the configuration is "directly" in rootfs. b. The con is there is need to provide a custom init to
guarantee the Overlay is mounted before the boot process.With the above information I'm proposing to use a separate partition for the configuration; this is because is more reliable and doesn't require big changes in the current architecture.
So, the idea is to have 4 partitions in the media:
1. boot. This is the usual boot partition
2. data. This will hold the configuration files. Not modified by updates.
3. maintenance. This partition will be used to update rootfs.
4. rootfs. Partition used for normal operation.Mariano
--
_______________________________________________
Openembedded-core mailing list [email protected] <mailto:[email protected]>
http://lists.openembedded.org/mailman/listinfo/openembedded-core
В письме от 23 ноября 2015 15:41:28 пользователь Mariano Lopez написал:
Quoted 5 lines
1. Use a separate partition for the configuration.
a. The pro of this method is the partition is not touched during the
update.
b. The con of this method is the configuration is not directly in
rootfs (example: /etc).
That's the right solution, although to do it really right (at least IMO) you need to implement the /usr merge [1] (and that's orthogonal to using or not using systemd), which can also help you make your /usr read-only (because that's just code and static data) with read-write / for user data of various sorts.
Quoted 5 lines
3. Have an OverlayFS for the rootfs or the partition that have the configuration.
a. The pro is the configuration is "directly" in rootfs. b. The con is there is need to provide a custom init to guarantee the
Overlay is mounted before the boot process.
And this is the approach I would recommend not doing. I've used UnionFS for thing like that (overlaying whole root file system) some 6 years ago, it sounded nice and it kinda worked, but it wasn't difficult to make it fail (just a little playing with power), we've even seen failures on production devices, like when you have whiteout file for directory already written, but don't have new files in it yet and that can completely ruin the system.
Also, it usually works better when you don't have any changes in the lower layer, but we're talking about updating it here, you can easily end up in a situation where you have updated something in the rootfs but that was overriden by upper layer and thus your user doesn't see any change.
Quoted 9 lines
With the above information I'm proposing to use a separate partition for the configuration; this is because is more reliable and doesn't require big changes in the current architecture.
So, the idea is to have 4 partitions in the media:
1. boot. This is the usual boot partition
2. data. This will hold the configuration files. Not modified by updates.
3. maintenance. This partition will be used to update rootfs.
4. rootfs. Partition used for normal operation.
You probably don't need to separate 1 and 3, all the code for system update should easily fit into initramfs and just making /boot a bit larger would allow you to store some backup rootfs.
Also, you can swap 4 and 2 which will be useful if you're installing on different sized storage devices, usually you know good enough the size of your rootfs, but you probably want to leave more space for user data if there is an opportunity to do so, that's just easier to do with data partition at the end.
[1] http://www.freedesktop.org/wiki/Software/systemd/TheCaseForTheUsrMerge/
Quoted 7 lines · Roman Khimov
В письме от 23 ноября 2015 15:41:28 пользователь Mariano Lopez написал:
Quoted 5 lines
1. Use a separate partition for the configuration.
a. The pro of this method is the partition is not touched during the
update.
b. The con of this method is the configuration is not directly in
rootfs (example: /etc).
Quoted 5 lines
That's the right solution, although to do it really right (at least IMO) you need to implement the /usr merge [1] (and that's orthogonal to using or not using systemd), which can also help you make your /usr read-only (because that's just code and static data) with read-write / for user data of various sorts.
Why does merging /usr have anything to do with this? I've read the case for merging /usr and / and still don't understand why it "helps". The key is that if you have separate partitions for /usr and /, then you need to update both of them in sequence. Merging these two just seems like a lazy solution to people not wanting to deal with early boot being self-contained.
Also having a separate / from /usr can help with '/' be your maintenance partition in some cases.
Quoted 13 lines
Quoted 5 lines
3. Have an OverlayFS for the rootfs or the partition that have the configuration.
a. The pro is the configuration is "directly" in rootfs. b. The con is there is need to provide a custom init to guarantee the
Overlay is mounted before the boot process.And this is the approach I would recommend not doing. I've used UnionFS for thing like that (overlaying whole root file system) some 6 years ago, it sounded nice and it kinda worked, but it wasn't difficult to make it fail (just a little playing with power), we've even seen failures on production devices, like when you have whiteout file for directory already written, but don't have new files in it yet and that can completely ruin the system.
Quoted 4 lines
Also, it usually works better when you don't have any changes in the lower layer, but we're talking about updating it here, you can easily end up in a situation where you have updated something in the rootfs but that was overriden by upper layer and thus your user doesn't see any change.
When using overlayfs, I'd strongly recommend not doing it over the entire rootfs. This is generally a bad idea for the reasons stated above.
However, overlaying a part of the rootfs often makes sense. /etc is a good example. This way applications that want their configurations in /etc can still have it that way -- and there is always a (hopefully) reasonable default configuration, should the configuration 'partition' get corrupted. So worst case the user can start over on configurations only.
For applications and user data, these can and should be stored outside of the main rootfs. The FHS/LSB recomment '/opt', but while it doesn't matter if it's -actually- /opt, the concept itself is good.
So going back to image upgrade. The key here is that you need a way to update arbitrary images with arbitrary contents and a mechanisms that is smart enough to generate the update (vs a full image flash) to conserve bandwidth.
I still contend it's up to the device to be able to configure the system on how to get the update and where to apply the update. The tooling (host and target) should simply assist with this.
Delta updates need version information in order to know they're doing the right sequence of updating.
Full updates don't, but should be sent in a format that limits "empty space", effectively send them as sparse files.
On many devices you will need to flash as part of the download due to space limitations.
And you need the ability to flash multiple partitions.
maintenance
/
/usr
data
etc.. whatever it takes to either upgrade or restore the device.
--Mark
Quoted 21 lines
Quoted 9 lines
With the above information I'm proposing to use a separate partition for the configuration; this is because is more reliable and doesn't require big changes in the current architecture.
So, the idea is to have 4 partitions in the media:
1. boot. This is the usual boot partition
2. data. This will hold the configuration files. Not modified by updates.
3. maintenance. This partition will be used to update rootfs.
4. rootfs. Partition used for normal operation.You probably don't need to separate 1 and 3, all the code for system update should easily fit into initramfs and just making /boot a bit larger would allow you to store some backup rootfs.
Also, you can swap 4 and 2 which will be useful if you're installing on different sized storage devices, usually you know good enough the size of your rootfs, but you probably want to leave more space for user data if there is an opportunity to do so, that's just easier to do with data partition at the end.
[1] http://www.freedesktop.org/wiki/Software/systemd/TheCaseForTheUsrMerge/
Quoted 37 lines · Mark Hatle
Quoted 11 lines · Roman Khimov
В письме от 23 ноября 2015 15:41:28 пользователь Mariano Lopez написал:
Quoted 5 lines
1. Use a separate partition for the configuration.
a. The pro of this method is the partition is not touched during the
update.
b. The con of this method is the configuration is not directly in
rootfs (example: /etc).That's the right solution, although to do it really right (at least IMO) you need to implement the /usr merge [1] (and that's orthogonal to using or not using systemd), which can also help you make your /usr read-only (because that's just code and static data) with read-write / for user data of various sorts.
Why does merging /usr have anything to do with this? I've read the case for merging /usr and / and still don't understand why it "helps". The key is that if you have separate partitions for /usr and /, then you need to update both of them in sequence. Merging these two just seems like a lazy solution to people not wanting to deal with early boot being self-contained.
Also having a separate / from /usr can help with '/' be your maintenance partition in some cases.
Quoted 12 lines
Quoted 5 lines
3. Have an OverlayFS for the rootfs or the partition that have the configuration.
a. The pro is the configuration is "directly" in rootfs. b. The con is there is need to provide a custom init to guarantee the
Overlay is mounted before the boot process.And this is the approach I would recommend not doing. I've used UnionFS for thing like that (overlaying whole root file system) some 6 years ago, it sounded nice and it kinda worked, but it wasn't difficult to make it fail (just a little playing with power), we've even seen failures on production devices, like when you have whiteout file for directory already written, but don't have new files in it yet and that can completely ruin the system.
Quoted 4 lines
Also, it usually works better when you don't have any changes in the lower layer, but we're talking about updating it here, you can easily end up in a situation where you have updated something in the rootfs but that was overriden by upper layer and thus your user doesn't see any change.
Quoted 8 lines
When using overlayfs, I'd strongly recommend not doing it over the entire rootfs. This is generally a bad idea for the reasons stated above.
However, overlaying a part of the rootfs often makes sense. /etc is a good example. This way applications that want their configurations in /etc can still have it that way -- and there is always a (hopefully) reasonable default configuration, should the configuration 'partition' get corrupted. So worst case the user can start over on configurations only.
Do you know a way to mount the overlay before all the services start? I tried to do this, but the only reliable way to do it was using a custom init, I couldn't accomplish this using systemd or sysvnit.
Quoted 9 lines
For applications and user data, these can and should be stored outside of the main rootfs. The FHS/LSB recomment '/opt', but while it doesn't matter if it's -actually- /opt, the concept itself is good.
So going back to image upgrade. The key here is that you need a way to update arbitrary images with arbitrary contents and a mechanisms that is smart enough to generate the update (vs a full image flash) to conserve bandwidth.
I was concerned about this too, not just bandwidth but resources in the target. Unfortunately I couldn't find an option that is generic enough to just provide the update. The idea is to integrate the tool into YP, not to develop a new one. Some of the tools that I checked needed to use btrfs partitions, need python in the target, or other constrains that make the update system impossible for a lot of targets.
Quoted 5 lines
I still contend it's up to the device to be able to configure the system on how to get the update and where to apply the update. The tooling (host and target) should simply assist with this.
Quoted 8 lines
Delta updates need version information in order to know they're doing the right sequence of updating.
Full updates don't, but should be sent in a format that limits "empty space", effectively send them as sparse files.
On many devices you will need to flash as part of the download due to space limitations.
The tool mentioned has this capability.
Quoted 9 lines
And you need the ability to flash multiple partitions.
maintenance
/
/usr
dataetc.. whatever it takes to either upgrade or restore the device.
Yes, that would be possible, the only limitation is that is not possible to flash the partition that is being used.
Quoted 23 lines
--Mark
Quoted 20 lines
Quoted 9 lines
With the above information I'm proposing to use a separate partition for the configuration; this is because is more reliable and doesn't require big changes in the current architecture.
So, the idea is to have 4 partitions in the media:
1. boot. This is the usual boot partition
2. data. This will hold the configuration files. Not modified by updates.
3. maintenance. This partition will be used to update rootfs.
4. rootfs. Partition used for normal operation.You probably don't need to separate 1 and 3, all the code for system update should easily fit into initramfs and just making /boot a bit larger would allow you to store some backup rootfs.
Also, you can swap 4 and 2 which will be useful if you're installing on different sized storage devices, usually you know good enough the size of your rootfs, but you probably want to leave more space for user data if there is an opportunity to do so, that's just easier to do with data partition at the end.
[1] http://www.freedesktop.org/wiki/Software/systemd/TheCaseForTheUsrMerge/
Quoted 49 lines · Mariano
Quoted 37 lines · Mark Hatle
Quoted 11 lines · Roman Khimov
В письме от 23 ноября 2015 15:41:28 пользователь Mariano Lopez написал:
Quoted 5 lines
1. Use a separate partition for the configuration.
a. The pro of this method is the partition is not touched during the
update.
b. The con of this method is the configuration is not directly in
rootfs (example: /etc).That's the right solution, although to do it really right (at least IMO) you need to implement the /usr merge [1] (and that's orthogonal to using or not using systemd), which can also help you make your /usr read-only (because that's just code and static data) with read-write / for user data of various sorts.
Why does merging /usr have anything to do with this? I've read the case for merging /usr and / and still don't understand why it "helps". The key is that if you have separate partitions for /usr and /, then you need to update both of them in sequence. Merging these two just seems like a lazy solution to people not wanting to deal with early boot being self-contained.
Also having a separate / from /usr can help with '/' be your maintenance partition in some cases.
Quoted 12 lines
Quoted 5 lines
3. Have an OverlayFS for the rootfs or the partition that have the configuration.
a. The pro is the configuration is "directly" in rootfs. b. The con is there is need to provide a custom init to guarantee the
Overlay is mounted before the boot process.And this is the approach I would recommend not doing. I've used UnionFS for thing like that (overlaying whole root file system) some 6 years ago, it sounded nice and it kinda worked, but it wasn't difficult to make it fail (just a little playing with power), we've even seen failures on production devices, like when you have whiteout file for directory already written, but don't have new files in it yet and that can completely ruin the system.
Quoted 4 lines
Also, it usually works better when you don't have any changes in the lower layer, but we're talking about updating it here, you can easily end up in a situation where you have updated something in the rootfs but that was overriden by upper layer and thus your user doesn't see any change.
Quoted 8 lines
When using overlayfs, I'd strongly recommend not doing it over the entire rootfs. This is generally a bad idea for the reasons stated above.
However, overlaying a part of the rootfs often makes sense. /etc is a good example. This way applications that want their configurations in /etc can still have it that way -- and there is always a (hopefully) reasonable default configuration, should the configuration 'partition' get corrupted. So worst case the user can start over on configurations only.
Quoted 3 lines
Do you know a way to mount the overlay before all the services start? I tried to do this, but the only reliable way to do it was using a custom init, I couldn't accomplish this using systemd or sysvnit.
In the past I've done this with an initrd, with a custom /sbin/init that mounted and then did a reexec for the real init system or ordered things in such a way that the overlay happened -very- early.
Quoted 10 lines
Quoted 9 lines
For applications and user data, these can and should be stored outside of the main rootfs. The FHS/LSB recomment '/opt', but while it doesn't matter if it's -actually- /opt, the concept itself is good.
So going back to image upgrade. The key here is that you need a way to update arbitrary images with arbitrary contents and a mechanisms that is smart enough to generate the update (vs a full image flash) to conserve bandwidth.
Quoted 6 lines
I was concerned about this too, not just bandwidth but resources in the target. Unfortunately I couldn't find an option that is generic enough to just provide the update. The idea is to integrate the tool into YP, not to develop a new one. Some of the tools that I checked needed to use btrfs partitions, need python in the target, or other constrains that make the update system impossible for a lot of targets.
Yup. I just want to make sure people know one tool isn't going to do everything.. and the integration of a single tool shouldn't restrict people for doing other things with custom tooling.
--Mark
Quoted 53 lines
Quoted 5 lines
I still contend it's up to the device to be able to configure the system on how to get the update and where to apply the update. The tooling (host and target) should simply assist with this.
Quoted 8 lines
Delta updates need version information in order to know they're doing the right sequence of updating.
Full updates don't, but should be sent in a format that limits "empty space", effectively send them as sparse files.
On many devices you will need to flash as part of the download due to space limitations.
The tool mentioned has this capability.
Quoted 9 lines
And you need the ability to flash multiple partitions.
maintenance
/
/usr
dataetc.. whatever it takes to either upgrade or restore the device.
Yes, that would be possible, the only limitation is that is not possible to flash the partition that is being used.
Quoted 23 lines
--Mark
Quoted 20 lines
Quoted 9 lines
With the above information I'm proposing to use a separate partition for the configuration; this is because is more reliable and doesn't require big changes in the current architecture.
So, the idea is to have 4 partitions in the media:
1. boot. This is the usual boot partition
2. data. This will hold the configuration files. Not modified by updates.
3. maintenance. This partition will be used to update rootfs.
4. rootfs. Partition used for normal operation.You probably don't need to separate 1 and 3, all the code for system update should easily fit into initramfs and just making /boot a bit larger would allow you to store some backup rootfs.
Also, you can swap 4 and 2 which will be useful if you're installing on different sized storage devices, usually you know good enough the size of your rootfs, but you probably want to leave more space for user data if there is an opportunity to do so, that's just easier to do with data partition at the end.
[1] http://www.freedesktop.org/wiki/Software/systemd/TheCaseForTheUsrMerge/
В письме от 24 ноября 2015 07:47:38 пользователь Mark Hatle написал:
Quoted 18 lines · Roman Khimov
Quoted 9 lines
В письме от 23 ноября 2015 15:41:28 пользователь Mariano Lopez написал:
Quoted 8 lines
1. Use a separate partition for the configuration.
a. The pro of this method is the partition is not touched during the
update.
b. The con of this method is the configuration is not directly in
Quoted 7 lines
Quoted 1 line
rootfs (example: /etc).
That's the right solution, although to do it really right (at least IMO) you need to implement the /usr merge [1] (and that's orthogonal to using or not using systemd), which can also help you make your /usr read-only (because that's just code and static data) with read-write / for user data of various sorts.
Quoted 6 lines
Why does merging /usr have anything to do with this? I've read the case for merging /usr and / and still don't understand why it "helps". The key is that if you have separate partitions for /usr and /, then you need to update both of them in sequence. Merging these two just seems like a lazy solution to people not wanting to deal with early boot being self-contained.
It helps in that you can achieve a clear separation of your software and users data (whatever that is, even if that's just some configuration files) and only update your part (which is /usr).
Quoted 4 lines
So going back to image upgrade. The key here is that you need a way to update arbitrary images with arbitrary contents and a mechanisms that is smart enough to generate the update (vs a full image flash) to conserve bandwidth.
In my experience, size is almost not an issue these days, at least if we're talking about something less than 100 MB, but updating the whole image is more reliable and easier to manage.
Signature · 3 lines
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Quoted 26 lines · Roman Khimov
В письме от 24 ноября 2015 07:47:38 пользователь Mark Hatle написал:
Quoted 18 lines · Roman Khimov
Quoted 9 lines
В письме от 23 ноября 2015 15:41:28 пользователь Mariano Lopez написал:
Quoted 8 lines
1. Use a separate partition for the configuration.
a. The pro of this method is the partition is not touched during the
update.
b. The con of this method is the configuration is not directly in
Quoted 7 lines
Quoted 1 line
rootfs (example: /etc).
That's the right solution, although to do it really right (at least IMO) you need to implement the /usr merge [1] (and that's orthogonal to using or not using systemd), which can also help you make your /usr read-only (because that's just code and static data) with read-write / for user data of various sorts.
Quoted 6 lines
Why does merging /usr have anything to do with this? I've read the case for merging /usr and / and still don't understand why it "helps". The key is that if you have separate partitions for /usr and /, then you need to update both of them in sequence. Merging these two just seems like a lazy solution to people not wanting to deal with early boot being self-contained.
Quoted 3 lines
It helps in that you can achieve a clear separation of your software and users data (whatever that is, even if that's just some configuration files) and only update your part (which is /usr).
This can easily be archived using different partitions like /opt as well.
Quoted 9 lines
Quoted 4 lines
So going back to image upgrade. The key here is that you need a way to update arbitrary images with arbitrary contents and a mechanisms that is smart enough to generate the update (vs a full image flash) to conserve bandwidth.
In my experience, size is almost not an issue these days, at least if we're talking about something less than 100 MB, but updating the whole image is more reliable and easier to manage.
Bandwidth is a big deal in areas that are not serviced by anything but very GPRS or worse. So 100 MB is even too big in some cases. Cost is a factor as is overall bandwidth.
Again, it depends on the product and what you are building if this matters.
The point is we don't want to make some assumptions that preclude alternative implementations.
--Mark
В письме от 24 ноября 2015 12:27:30 пользователь Mark Hatle написал:
Quoted 27 lines · Roman Khimov
Quoted 26 lines
В письме от 24 ноября 2015 07:47:38 пользователь Mark Hatle написал:
Quoted 24 lines · Roman Khimov
Quoted 9 lines
В письме от 23 ноября 2015 15:41:28 пользователь Mariano Lopez написал:
Quoted 8 lines
1. Use a separate partition for the configuration.
a. The pro of this method is the partition is not touched during the
update.
b. The con of this method is the configuration is not directly in
Quoted 7 lines
Quoted 1 line
rootfs (example: /etc).
That's the right solution, although to do it really right (at least IMO) you need to implement the /usr merge [1] (and that's orthogonal to using or not using systemd), which can also help you make your /usr read-only (because that's just code and static data) with read-write / for user data of various sorts.
Why does merging /usr have anything to do with this? I've read the case for merging /usr and / and still don't understand why it "helps". The key is that if you have separate partitions for /usr and /, then you need to update both of them in sequence. Merging these two just seems like a lazy solution to people not wanting to deal with early boot being self-contained.
Quoted 5 lines
Quoted 3 lines
It helps in that you can achieve a clear separation of your software and users data (whatever that is, even if that's just some configuration files) and only update your part (which is /usr).
This can easily be archived using different partitions like /opt as well.
Usually it leads to more complicated partitioning and more complicated startup (as well as update) procedure. Of course it can vary from system to system, but in my experience /usr merge was exactly the thing needed to clearly separate and simplify things. One way or another you want to have your code and users data to be separated, /usr merge makes it quite simple.
Quoted 8 lines
Bandwidth is a big deal in areas that are not serviced by anything but very GPRS or worse. So 100 MB is even too big in some cases. Cost is a factor as is overall bandwidth.
Again, it depends on the product and what you are building if this matters.
The point is we don't want to make some assumptions that preclude alternative implementations.
Sure.
Signature · 3 lines
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Quoted 39 lines · Roman Khimov
В письме от 24 ноября 2015 12:27:30 пользователь Mark Hatle написал:
Quoted 24 lines · Roman Khimov
Quoted 23 lines
В письме от 24 ноября 2015 07:47:38 пользователь Mark Hatle написал:
Quoted 22 lines · Roman Khimov
Quoted 7 lines
В письме от 23 ноября 2015 15:41:28 пользователь Mariano Lopez написал:
Quoted 6 lines
1. Use a separate partition for the configuration.
a. The pro of this method is the partition is not touched during the
update.
Quoted 8 lines
Quoted 3 lines
b. The con of this method is the configuration is not directly in
rootfs (example: /etc).
That's the right solution, although to do it really right (at least IMO) you need to implement the /usr merge [1] (and that's orthogonal to using or not using systemd), which can also help you make your /usr read-only (because that's just code and static data) with read-write / for user data of various sorts.
Why does merging /usr have anything to do with this? I've read the case for merging /usr and / and still don't understand why it "helps". The key is that if you have separate partitions for /usr and /, then you need to update both of them in sequence. Merging these two just seems like a lazy solution to people not wanting to deal with early boot being self-contained.
Quoted 4 lines
Quoted 3 lines
It helps in that you can achieve a clear separation of your software and users data (whatever that is, even if that's just some configuration files) and only update your part (which is /usr).
This can easily be archived using different partitions like /opt as well.
Usually it leads to more complicated partitioning and more complicated startup (as well as update) procedure. Of course it can vary from system to system, but in my experience /usr merge was exactly the thing needed to clearly separate and simplify things. One way or another you want to have your code and users data to be separated, /usr merge makes it quite simple.
Quoted 4 lines
Bandwidth is a big deal in areas that are not serviced by anything but very GPRS or worse. So 100 MB is even too big in some cases. Cost is a factor as is overall bandwidth.
Quoted 6 lines
Quoted 4 lines
Again, it depends on the product and what you are building if this matters.
The point is we don't want to make some assumptions that preclude alternative implementations.
Sure.
Thanks to all for your input. The conclusion of this thread is:
1. One size doesn't fit all.
2. Most of the people was fine with the image based update.
3. The recommended way to keep the configuration is to have a separated data partition.
4. The partition scheme would be:
1. boot. This is the usual boot partition
2. rootfs. Partition used for normal operation.
3. maintenance. This partition will be used to update rootfs.
4. data. This will hold the configuration files. Not modified by updates.
Signature · 1 line
Mariano Lopez
Quoted 9 lines
Am 03.12.2015 um 17:45 schrieb Mariano Lopez <[email protected]>:
[...]
Thanks to all for your input. The conclusion of this thread is:
1. One size doesn't fit all.
2. Most of the people was fine with the image based update.
Where is the image stored? I read over referred http://sbabic.github.io/swupdate/
and realized that the update image must include a stripped rootfs and the entire software for rootfs as well as probably the recoveryfs/maintfs and some logic for updating the data volume (eg. migrator for database of business logic).
This can be very large ... and must be stored somewhere.
Next question: how bullet proof is the swupdate?
Out process is designed (because of typical users can't interact) to can survive surprising power outage. Unfortunately we didn't manage to split out u-boot into separate updatable parts, so we can't benefit from it - but technically (if one has implemented for heir targets), our script updates and continues after power comes back.
I think, beside the question of having an image containing the update (we have such an add-on, too - for legacy devices without he modern Yocto based firmware), the question of stability should be evaluated, too.
Quoted 7 lines
3. The recommended way to keep the configuration is to have a separated data partition.
4. The partition scheme would be:
1. boot. This is the usual boot partition
2. rootfs. Partition used for normal operation.
3. maintenance. This partition will be used to update rootfs.
4. data. This will hold the configuration files. Not modified by updates.
Cheers
Signature · 1 line
Jens Rehsack - [email protected]
A message that is not in the archive (sent off-list or not yet received): [email protected]
Quoted 11 lines · Roman Khimov
В письме от 23 ноября 2015 15:41:28 пользователь Mariano Lopez написал:
Quoted 5 lines
1. Use a separate partition for the configuration.
a. The pro of this method is the partition is not touched during the
update.
b. The con of this method is the configuration is not directly in
rootfs (example: /etc).That's the right solution, although to do it really right (at least IMO) you need to implement the /usr merge [1] (and that's orthogonal to using or not using systemd), which can also help you make your /usr read-only (because that's just code and static data) with read-write / for user data of various sorts.
To be honest I'm not familiar with /usr merge, I need to check on that to see if it is a good option with the current OE-core infrastructure.
Quoted 13 lines
Quoted 6 lines
3. Have an OverlayFS for the rootfs or the partition that have the configuration.
a. The pro is the configuration is "directly" in rootfs. b. The con is there is need to provide a custom init to guarantee the
Overlay is mounted before the boot process.And this is the approach I would recommend not doing. I've used UnionFS for thing like that (overlaying whole root file system) some 6 years ago, it sounded nice and it kinda worked, but it wasn't difficult to make it fail (just a little playing with power), we've even seen failures on production devices, like when you have whiteout file for directory already written, but don't have new files in it yet and that can completely ruin the system.
Quoted 4 lines
Also, it usually works better when you don't have any changes in the lower layer, but we're talking about updating it here, you can easily end up in a situation where you have updated something in the rootfs but that was overriden by upper layer and thus your user doesn't see any change.
Thanks for sharing your experience, this is another big con for the Overlay option.
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Quoted 5 lines
With the above information I'm proposing to use a separate partition for the configuration; this is because is more reliable and doesn't require big changes in the current architecture.
Quoted 8 lines
Quoted 5 lines
So, the idea is to have 4 partitions in the media:
1. boot. This is the usual boot partition
2. data. This will hold the configuration files. Not modified by updates.
3. maintenance. This partition will be used to update rootfs.
4. rootfs. Partition used for normal operation.You probably don't need to separate 1 and 3, all the code for system update should easily fit into initramfs and just making /boot a bit larger would allow you to store some backup rootfs.
I left the /boot partition separate just in case there is need to replace the kernel or the bootloader. This way it would be easier to change using the same method as the upgrading the rootfs.
Quoted 5 lines
Also, you can swap 4 and 2 which will be useful if you're installing on different sized storage devices, usually you know good enough the size of your rootfs, but you probably want to leave more space for user data if there is an opportunity to do so, that's just easier to do with data partition at the end.
I was thinking in the same thinking just backwards, usually configuration files are just small text files that don't require too much space. If you require a new feature in the target that will make rootfs to grow depending on the feature. I plan to use wic to accomplish the filesystem structure. A good thing about wic is that it will be very easy to do the swap, just need to modify two options in the .wks file.
Quoted 3 lines
[1] http://www.freedesktop.org/wiki/Software/systemd/TheCaseForTheUsrMerge/
В письме от 24 ноября 2015 10:30:17 пользователь Lopez, Mariano написал:
Quoted 8 lines
Quoted 5 lines
That's the right solution, although to do it really right (at least IMO) you need to implement the /usr merge [1] (and that's orthogonal to using or not using systemd), which can also help you make your /usr read-only (because that's just code and static data) with read-write / for user data of various sorts.
To be honest I'm not familiar with /usr merge, I need to check on that to see if it is a good option with the current OE-core infrastructure.
It needs some patches for current OE, I hope I'll find some time to rebase the set I have for this (based on fido) and send it for discussion.
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