[gentoo-user] Docker + systemd since cgroups v2

[gentoo-user] Docker + systemd since cgroups v2

[Andrew Udvare]

For reference: uname -r: 5.2.13-gentoo, systemd version 243_rc2-r1[cgroup-hybrid], ACCEPT_KEYWORDS="~amd64"

My system started failing to start running docker.service automatically and the logs weren't too helpful. Finally I ran dockerd on its own and found that it gave me this error message:

Devices cgroup isn't mounted

This is not too easy to diagnose as there seem to be a set of solutions but none of the main two worked for me. One involved setting 2 options on the kernel command line:

cgroup_enable=memory swapaccount=1

And the other was to add USE="cgroup-hybrid" to systemd. I did this, but it too it did not work.

The other solution is to simply mount the cgroup manually and this works but I did not see why I'd have to do that now when I never had to in the past.

I actually had to add this to my command line:

systemd.legacy_systemd_cgroup_controller=yes

This has been noted in other distros but from what I can tell this is solely because runc has not been updated to be able to use cgroups v2.

Anyone else ran into this issue? Is there something I am missing so I wouldn't need to pass a kernel command line option?

Reference links:

https://docs.docker.com/install/linux/linux-postinstall/#your-kernel-does-not-support-cgroup-swap-limit-capabilities
https://github.com/opencontainers/runc/issues/654
https://github.com/opencontainers/runc/issues/1175
https://wiki.gentoo.org/wiki/Docker#Docker_service_fails_because_cgroup_device_not_mounted_.28systemd.29


-- 
Andrew Udvare

Re: [gentoo-user] Docker + systemd since cgroups v2

[John Covici]

On Tue, 10 Sep 2019 10:12:08 -0400,
Andrew Udvare wrote:
> 
> For reference: uname -r: 5.2.13-gentoo, systemd version 243_rc2-r1[cgroup-hybrid], ACCEPT_KEYWORDS="~amd64"
> 
> My system started failing to start running docker.service automatically and the logs weren't too helpful. Finally I ran dockerd on its own and found that it gave me this error message:
> 
> Devices cgroup isn't mounted
> 
> This is not too easy to diagnose as there seem to be a set of solutions but none of the main two worked for me. One involved setting 2 options on the kernel command line:
> 
> cgroup_enable=memory swapaccount=1
> 
> And the other was to add USE="cgroup-hybrid" to systemd. I did this, but it too it did not work.
> 
> The other solution is to simply mount the cgroup manually and this works but I did not see why I'd have to do that now when I never had to in the past.
> 
> I actually had to add this to my command line:
> 
> systemd.legacy_systemd_cgroup_controller=yes
> 
> This has been noted in other distros but from what I can tell this is solely because runc has not been updated to be able to use cgroups v2.
> 
> Anyone else ran into this issue? Is there something I am missing so I wouldn't need to pass a kernel command line option?
> 
> Reference links:
> 
> https://docs.docker.com/install/linux/linux-postinstall/#your-kernel-does-not-support-cgroup-swap-limit-capabilities
> https://github.com/opencontainers/runc/issues/654
> https://github.com/opencontainers/runc/issues/1175
> https://wiki.gentoo.org/wiki/Docker#Docker_service_fails_because_cgroup_device_not_mounted_.28systemd.29

I ran into this issue when going from 4.19.56 to 4.19.68 kernel.
Perhaps I will try this option later on, but I wonder if we could file
a bug with sgentoo or somewhere?

-- 
Your life is like a penny.  You're going to lose it.  The question is:
How do
you spend it?

         John Covici wb2una
         covici@ccs.covici.com

Re: [gentoo-user] Docker + systemd since cgroups v2

[John Covici]

On Tue, 10 Sep 2019 12:00:07 -0400,
John Covici wrote:
> 
> On Tue, 10 Sep 2019 10:12:08 -0400,
> Andrew Udvare wrote:
> > 
> > For reference: uname -r: 5.2.13-gentoo, systemd version 243_rc2-r1[cgroup-hybrid], ACCEPT_KEYWORDS="~amd64"
> > 
> > My system started failing to start running docker.service automatically and the logs weren't too helpful. Finally I ran dockerd on its own and found that it gave me this error message:
> > 
> > Devices cgroup isn't mounted
> > 
> > This is not too easy to diagnose as there seem to be a set of solutions but none of the main two worked for me. One involved setting 2 options on the kernel command line:
> > 
> > cgroup_enable=memory swapaccount=1
> > 
> > And the other was to add USE="cgroup-hybrid" to systemd. I did this, but it too it did not work.
> > 
> > The other solution is to simply mount the cgroup manually and this works but I did not see why I'd have to do that now when I never had to in the past.
> > 
> > I actually had to add this to my command line:
> > 
> > systemd.legacy_systemd_cgroup_controller=yes
> > 
> > This has been noted in other distros but from what I can tell this is solely because runc has not been updated to be able to use cgroups v2.
> > 
> > Anyone else ran into this issue? Is there something I am missing so I wouldn't need to pass a kernel command line option?
> > 
> > Reference links:
> > 
> > https://docs.docker.com/install/linux/linux-postinstall/#your-kernel-does-not-support-cgroup-swap-limit-capabilities
> > https://github.com/opencontainers/runc/issues/654
> > https://github.com/opencontainers/runc/issues/1175
> > https://wiki.gentoo.org/wiki/Docker#Docker_service_fails_because_cgroup_device_not_mounted_.28systemd.29
> 
> I ran into this issue when going from 4.19.56 to 4.19.68 kernel.
> Perhaps I will try this option later on, but I wonder if we could file
> a bug with sgentoo or somewhere?

And furthermore its the same version of systemd 243_rc2 .

-- 
Your life is like a penny.  You're going to lose it.  The question is:
How do
you spend it?

         John Covici wb2una
         covici@ccs.covici.com