In this article, we will look at the kubectl cp
command, its definition, and syntax, before showing how to use it to perform practical everyday tasks, such as copying files from a pod to your local system. We will also take a look at some common errors associated with kubectl cp
, explaining the common causes and how to go about troubleshooting them.
We will cover:
The kubectl cp
is a command-line utility in Kubernetes used to copy files and directories to and from a container in a Kubernetes pod. It allows you to transfer files between your local system and a running container within a pod without needing to set up additional tools or services.
kubectl cp
is only available for pods running a compatible version of the K8S API server (v1.14+). It can be a convenient way to transfer files in and out of containers when needed for troubleshooting, debugging, or data exchange.
Command syntax
The example usage of the kubectl cp
command is shown below:
kubectl cp <source> <destination> -n <namespace> <pod-name>:<path>
<source>
: The source file or directory on your local system or in the container (use.
to represent the current directory in the container).<destination>
: The destination on your local system or in the container.-n <namespace>
: Specifies the namespace in which the pod is running (optional).<pod-name>
: The name of the pod where you want to copy files.<path>
: The path within the container where you want to copy files or directories.
Let’s look at some use case examples for the kubectl cp
command.
Example 1 — Copying files from pod to local system
To copy files from a pod to the local system use:
kubectl cp -n <namespace> <pod-name>:<path> <destination-on-local-system>
For example, if you have a pod named “my-pod” in the “default” namespace and you want to copy a file named “file.txt” from the pod to your local system, you can use the following command:
kubectl cp -n default my-pod:/path/to/file.txt .
Note the .
represents the current directory.
Example 2 — Copying files from local system to pod
Now, to copy files from the local system to a pod:
kubectl cp -n <namespace> <source> <pod-name>:<path>
For example, if you have a pod named “my-pod” in the “default” namespace and you want to copy a file named “file.txt” from your local system to the pod, you can use the following command:
kubectl cp -n default . my-pod:/path/to/file.txt
Example 3 — Copying files from a pod to a pod
To copy files from one pod to another pod in K8S using the kubectl cp
command, you will need to copy the files to your local system as an intermediate step and then from your local system to the destination pod.
You can use the two examples above to achieve this.
Example 4 — Copying files from a pod in a specific namespace to local system
The -n
option in the kubectl cp
command is used to point out a specific namespace.
kubectl cp -n <namespace> <pod-name>:<path> <destination-on-local-system>
For example, if you have a pod named “my-pod” in the “test” namespace and you want to copy a file named “file.txt” from the pod to your local system, you can use the following command:
kubectl cp -n test my-pod:/path/to/file.txt .
Example 4 — Copying directories
Instead of specifying files to copy, you can also specify directories. For example, to copy a directory from your local system to a pod:
kubectl cp /path/to/local/directory <namespace>/<pod-name>:/path/in/pod
Example 5 — Copying from a specific container
You can also use kubectl cp
to copy files between containers within the same pod.
kubectl cp -n <namespace> <pod-name>:<source-container>:<path> <destination-container>:<destination-path>
kubectl cp
command errors can occur for various reasons, and troubleshooting them depends on the specific error message you encounter. Some common errors are described below.
Kubectl cp unexpected EOF error
The “unexpected EOF” error when using kubectl cp
typically indicates that the kubectl cp
command received an incomplete or unexpected response from the Kubernetes cluster. This can occur for various reasons but is commonly caused by network issues or unexpected interruptions in the transfer process.
How to fix it?
To resolve the issue, check the networking is configured correctly, that the cluster is healthy and responding correctly, and that the container and pod you are targeting are responding as expected. Also, check you have enough disk space available for the file transfer on the source and target.
Kubectl cp terminated with exit code 126
The “terminated with exit code 126” error when using kubectl cp
usually indicates that the command failed because it was unable to find or execute a specific executable or script in the target container. Exit code 126 typically means “Permission denied”.
How to fix it?
To resolve the issue, check you have permissions on the file you’re trying to copy, that it is readable, or that the script you’re trying to run is executable. If the file or command you’re trying to access is not found in the specified path, you’ll encounter this error.
- Double-check the paths and arguments in your
kubectl cp
command. - Verify that the file or command exists in the container.
- Check the container is running and is responding correctly.
- Also, check that the file you’re trying to copy or execute is in a compatible format with the container’s operating system. For example, a binary compiled for Linux won’t work in a Windows container.
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The kubectl cp
command can be used to transfer files and directories between your local machine and pods, or between pods running on your K8S cluster.
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