stern

Stern allows you to tail multiple pods on Kubernetes and multiple containers within the pod. Each result is color coded for quicker debugging.

The query is a regular expression so the pod name can easily be filtered and you don't need to specify the exact id (for instance omitting the deployment id). If a pod is deleted it gets removed from tail and if a new is added it automatically gets tailed.

When a pod contains multiple containers Stern can tail all of them too without having to do this manually for each one. Simply specify the container flag to limit what containers to show. By default all containers are listened to.

Installation

If you don't want to build from source go grab a binary release

Govendor is required to install vendored dependencies.

mkdir -p $GOPATH/src/github.com/wercker
cd $GOPATH/src/github.com/wercker
git clone git@github.com:wercker/stern.git && cd stern
govendor sync
go install

Usage

stern [options] <pod>

The pod query is a regular expression so you could provide "web-\w" to tail web-backend and web-frontend pods but not web-123.

cli flags

flag	default	purpose
--container	.*	Container name when multiple containers in pod (regular expression)
--timestamps		Print timestamps
--since		Return logs newer than a relative duration like 52, 2m, or 3h. Displays all if omitted
--context		Kubernetes context to use. Default to kubectl config current-context
--exclude		Log lines to exclude; specify multiple with additional --exclude; (regular expression)
--namespace		Kubernetes namespace to use. Default to namespace configured in Kubernetes context
--kube-config	~/.kube/config	Path to kubeconfig file to use
--all-namespaces		If present, tail across all namespaces. A specific namespace is ignored even if specified with --namespace.
--selector		Selector (label query) to filter on. If present, default to .* for the pod-query.
--tail	-1	The number of lines from the end of the logs to show. Defaults to -1, showing all logs.
--color	auto	Force set color output. auto: colorize if tty attached, always: always colorize, never: never colorize

See stern --help for details

Examples:

Tail the gateway container running inside of the envvars pod on staging

stern --context staging --container gateway envvars

Show auth activity from 15min ago with timestamps

stern -t --since 15m auth

Follow the development of some-new-feature in minikube

stern --context minikube some-new-feature

View pods from another namespace

stern --namespace kube-system kubernetes-dashboard

Tail the pods filtered by run=nginx label selector across all namespaces

stern --all-namespaces -l run=nginx

Follow the frontend pods in canary release

stern --selector release=canary frontend