Cannot run `docker top`on user containers.

[bribass]

RancherOS Version: (ros os version) v1.3.0

Where are you running RancherOS? (docker-machine, AWS, GCE, baremetal, etc.) bare metal

It is not possible to run docker top to see what processes are running inside a non-system container.

rancher@gamma:~$ docker run -dt alpine cat
5f319428bd574629f847b659df0209345ae78200264376b5612a58c8632fba1
rancher@gamma:~$ docker top 5f319428bd57
Error response from daemon: Error running ps: exec: "ps": executable file not found in $PATH

Note that I can successfully run sudo system-docker top docker, which implies that there's a ps executable available to the system, but not to user-docker.

This makes it so that my Jenkins pipelines (that I'm trying to move to this new ROS box) will not be able to run their docker.image().inside {} steps. (Jenkins is using this container start with cat, using top to check that it started, and then running commands in this container with exec calls.)

[kuhnroyal]

Exactly same problem for me, just wanted to add an issue for this as well.

Also I just noted, that this is a problem with the ubuntu console only. I tried the default console and it works. However I need the ubuntu console to install some additional tools, git etc.

Edit:
This also happens with debian and alpine console, only default seems to work. I would guess it fails with all but the default.

[bribass]

Nice catch! I can confirm that I was using the debian console, and that by switching back to default, docker top works as expected.

[inthroxify]

If anyone would like a workaround:

sudo ln -s /bin/ps /usr/bin/ps

[niusmallnan]

This has been fixed in ROS v1.4.0.

[root@ip-172-31-26-213 rancher]# ros -v
version v1.4.0 from os image rancher/os:v1.4.0

[root@ip-172-31-26-213 rancher]# docker run -d --name test nginx
54d78d61a01c9ce79f12784475ed88c548a6d600e356bf0c5ece16849bf6dfac
[root@ip-172-31-26-213 rancher]# docker ps
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS               NAMES
54d78d61a01c        nginx               "nginx -g 'daemon ..."   3 seconds ago       Up 2 seconds        80/tcp              test
[root@ip-172-31-26-213 rancher]# docker top test
PID                 USER                COMMAND
2109                root                nginx: master process nginx -g daemon off;
2134                101                 nginx: worker process

[olljanat]

@niusmallnan looks that this issue still exists on v1.4.1 😢
and workaround told by @inthroxify is still needed.

[niusmallnan]

Reopen it, I may miss something.