stern-commando: opties en 11 voorbeelden

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Wat het doet

kubectl logs shows one pod. stern takes a pod query (a regex, a deployment, a label selector) and follows the logs of every matching pod and container, also of new pods that start later. Each pod gets its own colour and a prefix.

Zo schrijf je het

stern [OPTIONS] QUERY

Opties 14

Meest gebruikt

Options

QUERY: Pod name regex, or deployment/NAME, statefulset/NAME.
-n, --namespace NS: Namespace (can repeat).
-A, --all-namespaces: All namespaces.
-l, --selector LABELS: Pods with these labels.
-c, --container REGEX: Only matching containers.
-s, --since 15m: Logs from the last 15 minutes.
--tail N: Start with the last N lines.
-i, --include REGEX: Only lines that match.
-e, --exclude REGEX: Hide lines that match.
-o, --output raw|json|extjson: Output format.
-t, --timestamps: Show timestamps.
--context NAME: Use another kube context.
--no-follow: Print and exit (do not follow).
--max-log-requests N: Limit parallel log streams.

Voorbeelden 11

$ als gewone gebruiker# als root (of met sudo)

1All pods of a deployment
```
$stern -n shop deployment/shop
```
2Pods by name regex in all namespaces
```
$stern -A '^ingress-nginx'
```

3Only errors from the last 30 minutes

$stern -n shop shop --since 30m -i 'ERROR|panic'

4Pods with a label
```
$stern -n shop -l app=shop,tier=api
```
5Only the app container, not the sidecar
```
$stern -n shop shop -c app
```
6Hide health check lines
```
$stern -n shop shop -e 'GET /health'
```

7With timestamps, last 50 lines, no follow

$stern -n shop shop --tail 50 -t --no-follow

8JSON logs to jq

$stern -n shop shop -o raw | jq -r 'select(.level=="error") | .msg'

9Watch a rollout in a second terminal

$kubectl rollout restart deploy/shop -n shop
$stern -n shop deployment/shop --since 1m

10Logs of a CronJob's pods
```
$stern -n jobs '^backup-' --since 2h
```
11Another cluster
```
$stern --context prod -n shop shop
```

Let op

Many pods mean many log streams to the API server; filter with a namespace and a selector.
stern shows only what the kubelet still has; old logs need a log system (Loki, Elasticsearch).

Tips om te onthouden

kubectl logs -f -l app=shop --all-containers --prefix is the built-in, simpler version.

Exitcodes

`0`	OK.
`1`	Error.

`stern`

Wat het doet

Zo schrijf je het

Opties 14

Options

Voorbeelden 11

1All pods of a deployment

2Pods by name regex in all namespaces

3Only errors from the last 30 minutes

4Pods with a label

5Only the app container, not the sidecar

6Hide health check lines

7With timestamps, last 50 lines, no follow

8JSON logs to jq

9Watch a rollout in a second terminal

10Logs of a CronJob's pods

11Another cluster

Let op

Tips om te onthouden

Exitcodes

Volledige handleiding

stern

Wat het doet

Zo schrijf je het

Opties 14

Options

Voorbeelden 11

1All pods of a deployment

2Pods by name regex in all namespaces

3Only errors from the last 30 minutes

4Pods with a label

5Only the app container, not the sidecar

6Hide health check lines

7With timestamps, last 50 lines, no follow

8JSON logs to jq

9Watch a rollout in a second terminal

10Logs of a CronJob's pods

11Another cluster

Let op

Tips om te onthouden

Exitcodes

Verwante commando's

Gebruikt in deze lessen

Volledige handleiding

`stern`