OC-ADM-DRAIN(1)

💅 oc adm drain 💅

okay bestie, welcome to the OC ADM(1) manual page — that’s the manual name, folded in right up top like a little name tag. This one lives in the Openshift CLI User Manuals, and it’s all about draining a node before maintenance. 💅

🫶 NAME 🫶

oc adm drain — drain node in preparation for maintenance. slay.

✨ SYNOPSIS ✨

oc adm drain [OPTIONS]

🦋 DESCRIPTION 🦋

okay so the whole point: drain gets a node ready for maintenance. The given node is marked unschedulable so new pods can’t arrive. If the API server supports eviction (⟨https://kubernetes.io/docs/concepts/workloads/pods/disruptions/⟩ eviction ⟨https://kubernetes.io/docs/concepts/workloads/pods/disruptions/⟩), then drain evicts the pods. Otherwise, it uses normal DELETE to delete the pods. no cap. ✨

drain evicts or deletes all pods except mirror pods (those can’t be deleted through the API server). If there are daemon set-managed pods, drain will not proceed without --ignore-daemonsets, and regardless it will not delete any daemon set-managed pods, because those pods would be immediately replaced by the daemon set controller, which ignores unschedulable markings. 😭

If there are any pods that are neither mirror pods nor managed by a replication controller, replica set, daemon set, stateful set, or job, then drain will not delete any pods unless you use --force. --force will also allow deletion to proceed if the managing resource of one or more pods is missing. 🔥

When you’re ready to put the node back into service, use oc adm uncordon, which will make the node schedulable again. periodt.

Diagram reference from the page: ⟨https://kubernetes.io/images/docs/oc⟩ adm_drain.svg. Workflow line: Workflowhttps://kubernetes.io/images/docs/oc adm_drain.svg. yes, that second one really has no space after Workflow — iykyk 💀

🎀 OPTIONS 🎀

• --chunk-size=500 — Ask for huge lists in chunks instead of dumping them all at once; pass 0 to disable chunking. 🍓
• --delete-emptydir-data=false — Keep going even if pods are using emptyDir — that’s local data that will be deleted when the node is drained. 😭
• --disable-eviction=false — Force drain to use delete even if eviction is supported. This bypasses checking PodDisruptionBudgets, so use with caution. 🚨
• --dry-run="none" — Must be "none", "server", or "client". If client strategy, only print the object that would be sent, without sending it. If server strategy, submit a server-side request without persisting the resource.
• --force=false — Continue even if there are pods that do not declare a controller.
• --grace-period=-1 — Period of time in seconds given to each pod to terminate gracefully. If negative, the default value specified in the pod will be used.
• --ignore-daemonsets=false — Ignore DaemonSet-managed pods.
• --pod-selector="" — Label selector to filter pods on the node.
• -l, --selector="" — Selector (label query) to filter on; supports '=', '==', '!=', 'in', 'notin'. (e.g. -l key1=value1,key2=value2,key3 in (value3)). Matching objects must satisfy all of the specified label constraints.
• --skip-wait-for-delete-timeout=0 — If a pod’s DeletionTimestamp is older than N seconds, skip waiting for the pod. Seconds must be greater than 0 to skip.
• --timeout=0 — The length of time to wait before giving up; zero means infinite.

👑 OPTIONS INHERITED FROM PARENT COMMANDS 👑

These are inherited from the parent commands, bestie — still important, still here. 🫶

• --as="" — Username to impersonate for the operation. User could be a regular user or a service account in a namespace.
• --as-group=[] — Group to impersonate for the operation; this flag can be repeated to specify multiple groups.
• --as-uid="" — UID to impersonate for the operation.
• --as-user-extra=[] — User extras to impersonate for the operation; this flag can be repeated to specify multiple values for the same key.
• --cache-dir="/homeless-shelter/.kube/cache" — Default cache directory.
• --certificate-authority="" — Path to a cert file for the certificate authority.
• --client-certificate="" — Path to a client certificate file for TLS.
• --client-key="" — Path to a client key file for TLS.
• --cluster="" — The name of the kubeconfig cluster to use.
• --context="" — The name of the kubeconfig context to use.
• --disable-compression=false — If true, opt-out of response compression for all requests to the server.
• --insecure-skip-tls-verify=false — If true, the server’s certificate will not be checked for validity. This will make your HTTPS connections insecure. 😭
• --kubeconfig="" — Path to the kubeconfig file to use for CLI requests.
• --kuberc="" — Path to the kuberc file to use for preferences. This can be disabled by exporting KUBECTL_KUBERC=false feature gate or turning off the feature KUBERC=off.
• --match-server-version=false — Require server version to match client version.
• -n, --namespace="" — If present, the namespace scope for this CLI request.
• --profile="none" — Name of profile to capture. One of (none|cpu|heap|goroutine|threadcreate|block|mutex).
• --profile-output="profile.pprof" — Name of the file to write the profile to.
• --request-timeout="0" — The length of time to wait before giving up on a single server request. Non-zero values should contain a corresponding time unit (e.g. 1s, 2m, 3h). A value of zero means don’t timeout requests.
• -s, --server="" — The address and port of the Kubernetes API server.
• --tls-server-name="" — Server name to use for server certificate validation. If it is not provided, the hostname used to contact the server is used.
• --token="" — Bearer token for authentication to the API server.
• --user="" — The name of the kubeconfig user to use.
• --warnings-as-errors=false — Treat warnings received from the server as errors and exit with a non-zero exit code.

🌈 EXAMPLE 🌈

# Drain node "foo", even if there are pods not managed by a replication controller, replica set, job, daemon set, or stateful set on it
oc adm drain foo --force

# As above, but abort if there are pods not managed by a replication controller, replica set, job, daemon set, or stateful set, and use a grace period of 15 minutes
oc adm drain foo --grace-period=900

⭐ SEE ALSO ⭐

oc-adm(1), — go check that one too, bestie. 🫶

🧚 HISTORY 🧚

June 2016, Ported from the Kubernetes man-doc generator — that’s the whole history entry, and it ate. 👑

---

source/version: Openshift / Openshift CLI User Manuals; date: June 2016. okay bye bestie, slay your maintenance window 💖✨