nsenter

Overview

Minimal scratch-based Docker image (~400KB) containing a single statically linked nsenter binary, built from util-linux sources.

Docker Image

docker pull ghcr.io/alexei-led/nsenter

Multi-arch: linux/amd64 and linux/arm64 (built natively, no QEMU emulation).

Note: Docker Hub images (alexeiled/nsenter) are deprecated and no longer updated. Docker Hub has introduced increasingly restrictive policies for open-source projects — including rate limits, image retention limits for free accounts, and removal of free Team organizations. We've moved exclusively to GitHub Container Registry (GHCR), which offers unlimited pulls for public packages with no retention restrictions.

Usage

Read the official nsenter man page.

Enter a Docker container's namespaces

# enter all namespaces of a running container
docker run -it --rm --privileged --pid=container:<container_name_or_ID> \
  ghcr.io/alexei-led/nsenter --all --target 1 -- su -

Enter the Docker host

# enter all namespaces of Docker host
docker run -it --rm --privileged --pid=host \
  ghcr.io/alexei-led/nsenter --all --target 1 -- su -

Enter a Kubernetes node

Use the helper script nsenter-node.sh to enter any Kubernetes node by creating a temporary privileged pod:

# list Kubernetes nodes
kubectl get nodes

NAME                                            STATUS   ROLES    AGE     VERSION
ip-192-168-151-104.us-west-2.compute.internal   Ready    <none>   6d17h   v1.30.0-eks
ip-192-168-171-140.us-west-2.compute.internal   Ready    <none>   5d10h   v1.30.0-eks

# enter selected node as root
./nsenter-node.sh ip-192-168-151-104.us-west-2.compute.internal

[root@ip-192-168-151-104 ~]#

The script creates a temporary pod with hostPID, hostNetwork, and tolerations for all taints — it is automatically cleaned up when you exit the shell.

Building

docker build --build-arg UTIL_LINUX_VER=2.41.3 -t nsenter .

CI/CD

Workflow	Trigger	What it does
CI	Push / PR	Hadolint + ShellCheck + build + integration tests
Build and Release	Tag push	Native multi-arch build → GHCR + GitHub Release

Releases are triggered by pushing a version tag (e.g., 2.41.3) matching the upstream util-linux version.

License

GPL-2.0