wellcast/kubetail

Simple bash script to tail Kubernetes logs from multiple pods at the same time

Kubetail

A bash script that enables you to aggregate (tail/follow) logs from multiple pods into one stream. This is the same as running "kubectl logs -f " but for multiple pods.

If available, this script will use multitail, an interactive, curses-based multi-pane log viewer, or it can manage the log viewing with a simple bash function. Using multitail, each pod name can be automatically associated with a corresponding colorscheme (using the pod "base" name) that controls the precise formatting and coloring of the viewed log files.

See the included multitail configuration file kube-multitail.conf.

Installation

Use make to install into reasonably standard places. There are two targets:

make install-home
make install-usr

Both will install the kubetail script, the kube-multitail.conf configuration file, and the man page kubetail.man into the corresponding sub-directories: bin, etc, and man, with the directory root being either: ~ or /usr/local.

Usage

To find the names of all your pods:

$ kubectl get pods

This will return a list looking something like this:

NAME                   READY     STATUS    RESTARTS   AGE
app1-v1-aba8y          1/1       Running   0          1d
app1-v1-gc4st          1/1       Running   0          1d
app1-v1-m8acl  		   1/1       Running   0          6d
app1-v1-s20d0  		   1/1       Running   0          1d
app2-v31-9pbpn         1/1       Running   0          1d
app2-v31-q74wg         1/1       Running   0          1d
my-demo-v5-0fa8o       1/1       Running   0          3h
my-demo-v5-yhren       1/1       Running   0          2h

To tail the logs of the two "app2" pods in one go simply do:

$ kubetail app2

If the pods are using multiple containers specify the container like this:

$ kubetail app2 -c container1

Supply -h for help and addtional options:

$ kubetail -h

To see what commands are being generated to tail the logs, use the -v option:

$ kubetail -v myapp

To see what commands would be generated and used, without actually invoking them, use the -N option:

$ kubetail -N myapp

To avoid using multitail, use the -T option:

$ multitail -T myapp

Known issues

When you press "ctrl+c" to end the log session you may end up with errors like this:

error: write /dev/stdout: broken pipe

This error is normal; it is the result of output pending from one or more log files being unread by the interrupted script.

See also: http://code.haleby.se/2015/11/13/tail-logs-from-multiple-pods-simultaneously-in-kubernetes/