GitHub - wercker/stern: ⎈ Multi pod and container log tailing for Kubernetes
source link: https://github.com/wercker/stern
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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:
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:
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 descriptionjson
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.
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