stern

Fork of discontinued wercker/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 or a Kubernetes resource in the form <resource>/<name> 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

Download binary

Download a binary release

Build from source

go install github.com/stern/stern@latest

asdf (Linux/macOS)

If you use asdf, you can install like this:

asdf plugin add stern
asdf install stern latest

Homebrew (Linux/macOS)

If you use Homebrew, you can install like this:

brew install stern

Krew (Linux/macOS/Windows)

If you use Krew which is the package manager for kubectl plugins, you can install like this:

kubectl krew install stern

WinGet (Windows)

If you're running on Windows, usually the actual best way is to use WinGet to install which is Windows' built-in package manager, you can install like this:

winget install stern.stern

Usage

stern pod-query [flags]

The pod-query is a regular expression or a Kubernetes resource in the form <resource>/<name>.

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

When the query is in the form <resource>/<name> (exact match), you can select all pods belonging to the specified Kubernetes resource, such as deployment/nginx. Supported Kubernetes resources are pod, replicationcontroller, service, daemonset, deployment, replicaset, statefulset and job.

cli flags

<!-- auto generated cli flags begin --->

flag | default | purpose -----------------------------|-------------------------------|--------- --all-namespaces, -A | false | If present, tail across all namespaces. A specific namespace is ignored even if specified with --namespace. --color | auto | Force set color output. 'auto': colorize if tty attached, 'always': always colorize, 'never': never colorize. --completion | | Output stern command-line completion code for the specified shell. Can be 'bash', 'zsh' or 'fish'. --condition | | The condition to filter on: [condition-name[=condition-value]. The default condition-value is true. Match is case-insensitive. Currently only supported with --tail=0 or --no-follow. --config | ~/.config/stern/config.yaml | Path to the stern config file --container, -c | .* | Container name when multiple containers in pod. (regular expression) --container-colors | | Specifies the colors used to highlight container names. Use the same format as --pod-colors. Defaults to the values of --pod-colors if omitted, and must match its length. --container-state | all | Tail containers with state in running, waiting, terminated, or all. 'all' matches all container states. To specify multiple states, repeat this or set comma-separated value. --context | | The name of the kubeconfig context to use --diff-container, -d | false | Display different colors for different containers. --ephemeral-containers | true | Include or exclude ephemeral containers. --exclude, -e | [] | Log lines to exclude. (regular expression) --exclude-container, -E | [] | Container name to exclude when multiple containers in pod. (regular expression) --exclude-pod | [] | Pod name to exclude. (regular expression) --field-selector | | Selector (field query) to filter on. If present, default to "." for the pod-query. --highlight, -H | [] | Log lines to highlight. (regular expression) --include, -i | [] | Log lines to include. (regular expression) --init-containers | true | Include or exclude init containers. --kubeconfig | | Path to the kubeconfig file to use for CLI requests. --max-log-requests | -1 | Maximum number of concurrent logs to request. Defaults to 50, but 5 when specifying --no-follow --namespace, -n | | Kubernetes namespace to use. Default to namespace configured in kubernetes context. To specify multiple namespaces, repeat this or set comma-separated value. --no-follow | false | Exit when all logs have been shown. --node | | Node name to filter on. --only-log-lines | false | Print only log lines --output, -o | default | Specify predefined template. Currently support: [default, raw, json, extjson, ppextjson] --pod-colors | | Specifies the colors used to highlight pod names. Provide colors as a comma-separated list using SGR (Select Graphic Rendition) sequences, e.g., "91,92,93,94,95,96". --prompt, -p | false | Toggle interactive prompt for selecting 'app.kubernetes.io/instance' label values. --selector, -l | | Selector (label query) to filter on. If present, default to "." for the pod-query. --show-hidden-options | false | Print a list of hidden options. --since, -s | 48h0m0s | Return logs newer than a relative duration like 5s, 2m, or 3h. --stdin | false | Parse logs from stdin. All Kubernetes related flags are ignored when it is set. --tail | -1 | The number of lines from the end of the logs to show. Defaults to -1, showing all logs. --template | | Template to use for log lines, leave empty to use --output flag. --template-file, -T | | Path to template to use for log lines, leave empty to use --output flag. It overrides --template option. --timestamps, -t | | Print timestamps with the specified format. One of 'default' or 'short' in the form '--timestamps=format' ('=' cannot be omitted). If specified but without value, 'default' is used. --timezone | Local | Set timestamps to specific timezone. --verbosity | 0 | Number of the log level verbosity --version, -v | false | Print the version and exit.

<!-- auto generated cli flags end --->

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.

config file

You can use the config file to change the default values of stern options. The default config file path is ~/.config/stern/config.yaml.

# <flag name>: <value>
tail: 10
max-log-requests: 999
timestamps: short

You can change the config file path with --config flag or STERNCONFIG environment variable.

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 | | extjson | Outputs extended JSON with colorized pod/container names | | ppextjson | Pretty-prints extended JSON with colorized pod/container names |

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 its