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 pod 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 https://github.com/wercker/stern.git && cd stern
govendor sync
go install

Homebrew

On macOS, you can also install Stern using Homebrew:

brew install stern

Usage

stern pod-query [flags]

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), --exclude-container, Container name to exclude when multiple containers in pod (regular expression), --container-state, running, Tail containers with status in running, waiting or terminated. Default to running., --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, --kubeconfig, ~/.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, --output, default, Specify predefined template. Currently support: [default, raw, json] See templates section, template, Template to use for log lines, leave empty to use --output flag, See stern --help for details

Stern will use the $KUBECONFIG environment variable if set. If both the
environment variable and --kubeconfig flag are passed the cli flag will be
used.

templates

stern supports outputting custom log messages. There are a few predefined
templates which you can use by specifying the --output flag:, output, description, -----------, -------------------------------------------------------------------------------------------------------, default, Displays the namespace, pod and container, and decorates it with color depending on --color, raw, Only outputs the log message itself, useful when your logs are json and you want to pipe them to jq, json, Marshals the log struct to json. Useful for programmatic purposes, It accepts a custom template through the --template flag, which will be
compiled to a Go template and then used for every log message. This Go template
will receive the following struct:, property, type, description, -----------------, --------, ---------------------------, Message, string, The log message itself, Namespace, string, The namespace of the pod, PodName, string, The name of the pod, ContainerName, string, The name of the container, The following functions are available within the template (besides the builtin
functions):, func, arguments, description, ---------, -----------------------, -----------------------------------------------------------------, json, object, Marshal the object and output it as a json text, color, color.Color, string, Wrap the text in color (.ContainerColor and .PodColor provided), ## Examples:

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

stern envvars --context staging --container gateway

Tail the staging namespace excluding logs from istio-proxy container

stern -n staging --exclude-container istio-proxy .

Show auth activity from 15min ago with timestamps

stern auth -t --since 15m

Follow the development of some-new-feature in minikube

stern some-new-feature --context minikube

View pods from another namespace

stern kubernetes-dashboard --namespace kube-system

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 frontend --selector release=canary

Pipe the log message to jq:

stern backend -o json, jq .

Only output the log message itself:

stern backend -o raw

Output using a custom template:

stern --template '{{.Message}} ({{.Namespace}}/{{.PodName}}/{{.ContainerName}})' backend

Output using a custom template with stern-provided colors:

stern --template '{{.Message}} ({{.Namespace}}/{{color .PodColor .PodName}}/{{color .ContainerColor .ContainerName}})' backend

Completion

Stern supports command-line auto completion for bash or zsh. stern --completion=(bash, zsh) outputs the shell completion code which work by being
evaluated in .bashrc, etc for the specified shell. In addition, Stern
supports dynamic completion for --namespace and --context. In order to use
that, kubectl must be installed on your environment.

If you use bash, stern bash completion code depends on the
bash-completion. On the macOS, you
can install it with homebrew as follows:

$ brew install bash-completion

Note that bash-completion must be sourced before sourcing the stern bash
completion code in .bashrc.

source <(brew --prefix)/etc/bash-completion
source <(stern --completion=bash)

If you use zsh, just source the stern zsh completion code in .zshrc.

source <(stern --completion=zsh)

Contributing to this repository

Oracle welcomes contributions to this repository from anyone. Please see
CONTRIBUTING for details.