linux-purge assumes current kernel needs to be installed in Docker container

[Julio Lajara]

I am unable to run linux-purge inside a Docker container because it assumes that the currently running kernel should always be installed and properly configured which is not a valid assumption when running Ubuntu inside a Docker containrer. When run in a Docker container, its using the kernel of the host, therefore your host could be Ubuntu 20.04 and the container could be running Ubuntu 16.04. Therefore, trying to use the --fix option is not a valid solution in this case which is what it suggests when exits with an error because 16.04 wont have access to the 20.04 kernel packages in the default upstream repos.

[Julio Lajara (ju2wheels)]

 The situation occurs when using automation testing around linux-purge using containers, its not something likely to be valid in a case outside of using containers, which is why you have the check there.

[Jarno Suni (jarnos)]

Oh, I am not familiar with containers. Can you check somehow from command line whether you are going to operate on kernels in a container or in a host?

[Julio Lajara (ju2wheels)]

Im not sure of a generalized way where this would work both in Docker
or LXC which im assuming would also hit this issue. It may just be
easier to add a flag to disable this check to enforce the current
running kernel be installed rather than force dependency on a tool to
determine this that may not be installed and leave it up to the end
user to set the CLI flag when using linux-purge inside a container.

A lot of the online recommendations for how to check if you are
running in a container are not things I would ever put into a prod
tool, are container engine specific, or not guaranteed to work.

On Tue, Nov 2, 2021 at 3:45 PM Jarno Suni <email address hidden> wrote:
>
> Oh, I am not familiar with containers. Can you check somehow from
> command line whether you are going to operate on kernels in a container
> or in a host?
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1949504
>
> Title:
> linux-purge assumes current kernel needs to be installed in Docker
> container
>
> Status in linux-purge:
> New
>
> Bug description:
> I am unable to run linux-purge inside a Docker container because it
> assumes that the currently running kernel should always be installed
> and properly configured which is not a valid assumption when running
> Ubuntu inside a Docker containrer. When run in a Docker container, its
> using the kernel of the host, therefore your host could be Ubuntu
> 20.04 and the container could be running Ubuntu 16.04. Therefore,
> trying to use the --fix option is not a valid solution in this case
> which is what it suggests when exits with an error because 16.04 wont
> have access to the 20.04 kernel packages in the default upstream
> repos.
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/linux-purge/+bug/1949504/+subscriptions
>

[Jarno Suni (jarnos)]

I installed Docker. Can you give me instructions on how to reproduce the bug?

[Julio Lajara (ju2wheels)]

Im using Ubuntu 18.04:

start docker container (This is just my own container with Ansible
preinstalled on top of Ubuntu 18.04 Docker image):

```
docker run -it ju2wheels/ansible-base:2.10.x-ubuntu-18.04
```

Get linux-purge, install some linux kernels so theres something there
to actually test removal, and then run linux purge:

```
apt-get update
apt-get install git linux-image-generic
git clone https://git.launchpad.net/linux-purge /opt/linux-purge
/opt/linux-purge/linux-purge --clear-boot --keep 0 --yes
```
It may need to have more CLI command dependencies explicitly installed
in the container but I havent gotten past the error its giving.

On Tue, Nov 2, 2021 at 5:45 PM Jarno Suni <email address hidden> wrote:
>
> I installed Docker. Can you give me instructions on how to reproduce the
> bug?
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1949504
>
> Title:
> linux-purge assumes current kernel needs to be installed in Docker
> container
>
> Status in linux-purge:
> New
>
> Bug description:
> I am unable to run linux-purge inside a Docker container because it
> assumes that the currently running kernel should always be installed
> and properly configured which is not a valid assumption when running
> Ubuntu inside a Docker containrer. When run in a Docker container, its
> using the kernel of the host, therefore your host could be Ubuntu
> 20.04 and the container could be running Ubuntu 16.04. Therefore,
> trying to use the --fix option is not a valid solution in this case
> which is what it suggests when exits with an error because 16.04 wont
> have access to the 20.04 kernel packages in the default upstream
> repos.
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/linux-purge/+bug/1949504/+subscriptions
>

[Jarno Suni (jarnos)]

I am using Ubuntu 20.04. When I run your command, it exits with error: "ansible-playbook: error: the following arguments are required: playbook"

[Jarno Suni (jarnos)]

BTW why do you want to install kernels in a container, if they are not used anyway?

[Julio Lajara (ju2wheels)]

We use Ansible inside of Docker to test the automation code we deploy
to actual servers.

On Wed, Nov 3, 2021 at 7:40 AM Jarno Suni <email address hidden> wrote:
>
> BTW why do you want to install kernels in a container, if they are not
> used anyway?
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1949504
>
> Title:
> linux-purge assumes current kernel needs to be installed in Docker
> container
>
> Status in linux-purge:
> Incomplete
>
> Bug description:
> I am unable to run linux-purge inside a Docker container because it
> assumes that the currently running kernel should always be installed
> and properly configured which is not a valid assumption when running
> Ubuntu inside a Docker containrer. When run in a Docker container, its
> using the kernel of the host, therefore your host could be Ubuntu
> 20.04 and the container could be running Ubuntu 16.04. Therefore,
> trying to use the --fix option is not a valid solution in this case
> which is what it suggests when exits with an error because 16.04 wont
> have access to the 20.04 kernel packages in the default upstream
> repos.
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/linux-purge/+bug/1949504/+subscriptions
>

[Jarno Suni (jarnos)]

I am still unable to start the docker container by the command line you gave, even as superuser. Is it because I have 20.04?

[Julio Lajara (ju2wheels)]

Im on 20.04 as well, it should work fine. Is your user in the `docker` group ? Otherwise you need to run the docker command to start the container as root using sudo.

[Jarno Suni (jarnos)]

Even if I add the docker group, the command complains about missing playbook argument.

[Julio Lajara (ju2wheels)]

Ok gotcha, my fault. Our container defaults to running ansible as the
default command.

So you can either use the default base Ubuntu docker image:

docker run -it ubuntu:18.04

or for mine override the entrypoint to be the bash shell:

docker run --entrypoint /bin/bash -it ju2wheels/ansible-base:2.10.x-ubuntu-18.04

On Thu, Nov 4, 2021 at 11:35 AM Jarno Suni <email address hidden> wrote:
>
> Even if I add the docker group, the command complains about missing
> playbook argument.
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1949504
>
> Title:
> linux-purge assumes current kernel needs to be installed in Docker
> container
>
> Status in linux-purge:
> Incomplete
>
> Bug description:
> I am unable to run linux-purge inside a Docker container because it
> assumes that the currently running kernel should always be installed
> and properly configured which is not a valid assumption when running
> Ubuntu inside a Docker containrer. When run in a Docker container, its
> using the kernel of the host, therefore your host could be Ubuntu
> 20.04 and the container could be running Ubuntu 16.04. Therefore,
> trying to use the --fix option is not a valid solution in this case
> which is what it suggests when exits with an error because 16.04 wont
> have access to the 20.04 kernel packages in the default upstream
> repos.
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/linux-purge/+bug/1949504/+subscriptions
>

[Jarno Suni (jarnos)]

Can you somehow save the container's state so that you don't have to install linux-image-generic and clone and change linux-purge on each run of docker? I see your ju2wheels/ansible-base:2.10.x-ubuntu-18.04 has git pre-installed.

[Jarno Suni (jarnos)]

I could change the script to support your use case. However, linux-purge was designed to work on Ubuntu system that has specific packages pre-installed that do not seem to be installed in the docker images. Those include: lsb-release which is needed with --debug and --info; whiptail (or preferably dialog) with --choose (and maybe with --fix); wget and man-db if you use the provided installation/updating/removing scripts.

[Jarno Suni (jarnos)]

Just curious, why you want to use linux-purge instead of unattended-upgrades for automatic kernel management?

[Julio Lajara (ju2wheels)]

OK, no problem. Ill find a different way to run the tests outside Docker.

On Tue, Nov 9, 2021 at 4:41 AM Jarno Suni <email address hidden> wrote:
>
> I could change the script to support your use case. However, linux-purge
> was designed to work on Ubuntu system that has specific packages pre-
> installed that do not seem to be installed in the docker images. Those
> include: lsb-release which is needed with --debug and --info; whiptail
> (or preferably dialog) with --choose (and maybe with --fix); wget and
> man-db if you use the provided installation/updating/removing scripts.
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1949504
>
> Title:
> linux-purge assumes current kernel needs to be installed in Docker
> container
>
> Status in linux-purge:
> Triaged
>
> Bug description:
> I am unable to run linux-purge inside a Docker container because it
> assumes that the currently running kernel should always be installed
> and properly configured which is not a valid assumption when running
> Ubuntu inside a Docker containrer. When run in a Docker container, its
> using the kernel of the host, therefore your host could be Ubuntu
> 20.04 and the container could be running Ubuntu 16.04. Therefore,
> trying to use the --fix option is not a valid solution in this case
> which is what it suggests when exits with an error because 16.04 wont
> have access to the 20.04 kernel packages in the default upstream
> repos.
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/linux-purge/+bug/1949504/+subscriptions
>

[Jarno Suni (jarnos)]

I could easily make lsb-release optional so --debug would not break. Interestingly, ubuntu:14.04 container has lsb-release by default. And you do not have to care about whiptail|dialog unless you use those features. And you do not need wget and man-db, if you use git to get linux-purge like you did. I could make it possible for you to run linux-purge, but it demands some work.

[Jarno Suni (jarnos)]

One odd thing about a docker container ubuntu:14.04 is that realpath utility is not available even though there is coreutils 8.21 installed and even coreutils 8.15 has it according to https://savannah.gnu.org/forum/forum.php?forum_id=7076

[Jarno Suni (jarnos)]

I think this is fixed in version 1.0.143-de4571a

[Jarno Suni (jarnos)]

Does it work for you now with --no-booted option?