Run Command in Application Pod via TrueNAS Shell

[HarryMuscle]

Is it possible with the Kubernetes that TrueNAS Scale uses to run a command inside an application pod from the TrueNAS shell without going into the application's pod's shell? Sort of the equivalent to the docker exec command?

Thanks,
Harry

 

[Kris Moore]

Right now the container backend used for Kubernetes is still docker, so you can run "docker ps" to find your specific pod, and then use "docker exec -it <pod> <command>" as usual.

 

[FrostyCat]

Yes you can. Also, my advice would be to skip docker altogether and use only kubectl.

Code:

k3s kubectl -n <NAMESPACE> exec -ti <POD> -- <COMMAND>
# the next command would get you a shell inside the container
# k3s kubectl -n <NAMESPACE> exec -ti <POD> -- bash

Useful links:

Kubectl Reference Docs

kubernetes.io

Kubectl Reference Docs

kubernetes.io

 

[FrostyCat]

Quick example:

Code:

root@nas[~]# k3s kubectl -n ix-jellyfin get pods
NAME                        READY   STATUS    RESTARTS   AGE
jellyfin-585c6ff5d8-kwcmt   1/1     Running   0          14h

root@nas[~]# k3s kubectl -n ix-jellyfin exec -ti jellyfin-585c6ff5d8-kwcmt -- bash
Defaulted container "jellyfin" out of: jellyfin, autopermissions (init)
I have no name!@jellyfin-585c6ff5d8-kwcmt:/$

 

[HarryMuscle]

Awesome.

Thanks,
Harry

 

[peterge]

Quick example:

Code:

root@nas[~]# k3s kubectl -n ix-jellyfin get pods
NAME                        READY   STATUS    RESTARTS   AGE
jellyfin-585c6ff5d8-kwcmt   1/1     Running   0          14h

root@nas[~]# k3s kubectl -n ix-jellyfin exec -ti jellyfin-585c6ff5d8-kwcmt -- bash
Defaulted container "jellyfin" out of: jellyfin, autopermissions (init)
I have no name!@jellyfin-585c6ff5d8-kwcmt:/$

Thanks for the command, i want to use this command, to export my documents in paperless-ng with a ?weekly? cron job into my home share, which backups to backblaze. However, i would like to get the cron job as automatic as possible, do you know a solution to get always the correct pod name behind exec -ti <pod_name> ?
Do you know a better way than running this crappy command:
k3s kubectl -n ix-paperless-ng exec -ti $(k3s kubectl -n ix-paperless-ng get pods | tail -n 1 | cut -d " " -f 1) -- document_exporter
It works, but it may be not the smartest thing to do...

root@truenas[~]# k3s kubectl -n ix-paperless-ng exec -ti $(k3s kubectl -n ix-paperless-ng get pods | tail -n 1 | cut -d " " -f 1) -- document_exporter Defaulted container "paperless-ng" out of: paperless-ng, autopermissions (init), hostpatch (init), postgresql-init (init) usage: manage.py document_exporter [-h] [-c] [-f] [-d] [--no-progress-bar] [--version] [-v {0,1,2,3}] [--settings SETTINGS] [--pythonpath PYTHONPATH] [--traceback] [--no-color] [--force-color] [--skip-checks] target manage.py document_exporter: error: the following arguments are required: target command terminated with exit code 2

 

[truecharts]

Thanks for the command, i want to use this command, to export my documents in paperless-ng with a ?weekly? cron job into my home share, which backups to backblaze. However, i would like to get the cron job as automatic as possible, do you know a solution to get always the correct pod name behind exec -ti <pod_name> ?
Do you know a better way than running this crappy command:
k3s kubectl -n ix-paperless-ng exec -ti $(k3s kubectl -n ix-paperless-ng get pods | tail -n 1 | cut -d " " -f 1) -- document_exporter
It works, but it may be not the smartest thing to do...

root@truenas[~]# k3s kubectl -n ix-paperless-ng exec -ti $(k3s kubectl -n ix-paperless-ng get pods | tail -n 1 | cut -d " " -f 1) -- document_exporter Defaulted container "paperless-ng" out of: paperless-ng, autopermissions (init), hostpatch (init), postgresql-init (init) usage: manage.py document_exporter [-h] [-c] [-f] [-d] [--no-progress-bar] [--version] [-v {0,1,2,3}] [--settings SETTINGS] [--pythonpath PYTHONPATH] [--traceback] [--no-color] [--force-color] [--skip-checks] target manage.py document_exporter: error: the following arguments are required: target command terminated with exit code 2

Pods are not designed to be reached from a Cronjob and are ephemeral, both in name and design.
So not likely to have an easy solution, though there are solutions out there :)

 

[googlehupf]

Thanks for the command, i want to use this command, to export my documents in paperless-ng with a ?weekly? cron job into my home share, which backups to backblaze. However, i would like to get the cron job as automatic as possible, do you know a solution to get always the correct pod name behind exec -ti <pod_name> ?
Do you know a better way than running this crappy command:
k3s kubectl -n ix-paperless-ng exec -ti $(k3s kubectl -n ix-paperless-ng get pods | tail -n 1 | cut -d " " -f 1) -- document_exporter
It works, but it may be not the smartest thing to do...

root@truenas[~]# k3s kubectl -n ix-paperless-ng exec -ti $(k3s kubectl -n ix-paperless-ng get pods | tail -n 1 | cut -d " " -f 1) -- document_exporter Defaulted container "paperless-ng" out of: paperless-ng, autopermissions (init), hostpatch (init), postgresql-init (init) usage: manage.py document_exporter [-h] [-c] [-f] [-d] [--no-progress-bar] [--version] [-v {0,1,2,3}] [--settings SETTINGS] [--pythonpath PYTHONPATH] [--traceback] [--no-color] [--force-color] [--skip-checks] target manage.py document_exporter: error: the following arguments are required: target command terminated with exit code 2

I was having the same problem. I'm doing my backup like this:
1. Mount an export volume to the paperless-ng deployment
2. a) have pre script running to a backup job where I run document_exporter --> to the mounted volume
b) sync the export volume to a AWS S3 Bucket with a cloud backup routine in Truenas

To get the pod from the deployment I use this command:

Code:

POD=$(k3s kubectl -n ix-paperless-ng get pods --no-headers | grep -E -v "(redis|postgresql|svclb)" | awk '{print $1}')
k3s kubectl -n ix-paperless-ng exec -it ${POD} -- python ./manage.py document_exporter ../export