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A kubectl plugin to access nodes or remote services using a SSH jump Pod
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yokawasa/kubectl-plugin-ssh-jump
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A kubectl plugin to SSH into Kubernetes nodes using a SSH jump host Pod
Ajump host Pod is an intermediary Pod or an SSH gateway to Kubernetes node machines, through which a connection can be made to the node machines.
Here is an scenario where you want to connect to Kubernetes node, but you have to go through a jump host Pod, because of firewalling, access privileges. etc. There is a number of valid reasons why the jump hosts are needed...
[NOTE]
- Kubectl versions >=
1.12.0(Preferred)
- As of Kubernetes 1.12, kubectl now allows adding external executables as subcommands. For more detail, seeExtend kubectl with plugins
- You can run the pluin with
kubectl ssh-jump ...- Kubectl versions <
1.12.0
- You still can run the plugin directly with
kubectl-ssh-jump ...
Table of Content
This plugin needs the following programs:
- ssh(1)
- ssh-agent(1)
- ssh-keygen(1)
This is a way to install kubectl-ssh-jump throughkrew. After installing krew by followingthis, you can install kubectl-ssh-jump like this:
$ kubectl krew install ssh-jump
Expected output would be like this:
Updated the local copy of plugin index.Installing plugin: ssh-jumpCAVEATS:\ | This plugin needs the following programs: | * ssh(1) | * ssh-agent(1) | | Please follow the documentation: https://github.com/yokawasa/kubectl-plugin-ssh-jump/Installed plugin: ssh-jumpOnce it's installed, run:
$ kubectl plugin listThe following kubectl-compatible plugins are available:/Users/yoichika/.krew/bin/kubectl-krew/Users/yoichika/.krew/bin/kubectl-ssh_jump$ kubectl ssh-jump
Install the plugin by copying the script in the $PATH of your shell.
# Get source$ git clone https://github.com/yokawasa/kubectl-plugin-ssh-jump.git$cd kubectl-plugin-ssh-jump$ chmod +x kubectl-ssh-jump# Add kubeclt-ssh-jump to the install path.$ sudo cp -p kubectl-ssh-jump /usr/local/bin
Once in the $PATH, run:
$ kubectl plugin listThe following kubectl-compatible plugins are available:/usr/local/bin/kubectl-ssh-jump$ kubectl ssh-jump
Usage: kubectl ssh-jump <dest_node> [options]Options: <dest_node> Destination node name or IP address dest_node must start from the following letters: ASCII letters 'a' through 'z' or 'A' through 'Z', the digits '0' through '9', or hyphen ('-' -u, --user <sshuser> SSH User name -i, --identity <identity_file> Identity key file, or PEM(Privacy Enhanced Mail) -p, --pubkey <pub_key_file> Public key file -P, --port <port> SSH port for target node SSH server (default:22) -a, --args <args> Args to exec in ssh session --skip-agent Skip automatically starting SSH agent and adding SSH Identity key into the agent before SSH login (=> You need to manage SSH agent by yourself) --cleanup-agent Clearning up SSH agent at the end The agent is NOT cleaned up in case that --skip-agent option is given --cleanup-jump Clearning up sshjump pod at the end Default: Skip cleaning up sshjump pod -h, --help Show this messageExample: Scenario1 - You have private & public SSH key on your side$ kubectl ssh-jump -u myuser -i ~/.ssh/id_rsa -p ~/.ssh/id_rsa.pub hostname Scenario2 - You have .pem file but you don't have public key on your side$ kubectl ssh-jump -u ec2-user -i ~/.ssh/mykey.pem hostnameusername,identity,pubkey,port options are cached, therefore you can omit these options afterward. The options are stored in a file named$HOME/.kube/kubectlssh/options
$ cat$HOME/.kube/kubectlssh/optionssshuser=myuseridentity=/Users/yokawasa/.ssh/id_rsa_k8spubkey=/Users/yokawasa/.ssh/id_rsa_k8s.pubport=22The plugin automatically check if there are anyssh-agents started running by the plugin, and startsssh-agentif it doesn't find anyssh-agent running and adds SSH Identity key into the agent before SSH login. If the command find that ssh-agent is already running, it doesn't start a new agent, and re-use the agent.Add--cleanup-agent option if you want to kill the created agent at the end of command.
In addtion, add--skip-agent option if you want to skip automatic startingssh-agent. This is actually a case where you already have ssh-agent managed or you want to manually start the agent.
Show all node list. Simply executingkubectl ssh-jump gives you the list of destination nodes as well as command usage
$ kubectl ssh-jumpUsage: kubectl ssh-jump<dest_node> [options]Options:<dest_node> Destination node name or IP address dest_node must start from the following letters: ASCII letters'a' through'z' or'A' through'Z', the digits'0' through'9', or hyphen ('-') -u, --user<sshuser> SSH User name -i, --identity<identity_file> Identity key file, or PEM(Privacy Enhanced Mail) -p, --pubkey<pub_key_file> Public key file -P, --port<port> SSH portfor target node SSH server (default:22) -a, --args<args> Args toexecin ssh session --skip-agent Skip automatically starting SSH agent and adding SSH Identity key into the agent before SSH login (=> You need to manage SSH agent by yourself) --cleanup-agent Clearning up SSH agent at the end The agent is NOT cleaned upincase that --skip-agent option is given --cleanup-jump Clearning up sshjump pod at the end Default: Skip cleaning up sshjump pod -h, --help Show this messageExample: Scenario1 - You have private& public SSH key on your side $ kubectl ssh-jump -u myuser -i~/.ssh/id_rsa -p~/.ssh/id_rsa.pub hostname Scenario2 - You have .pem file but you don't have public key on your side $ kubectl ssh-jump -u ec2-user -i ~/.ssh/mykey.pem hostnameList of destination node...Hostname Internal-IPaks-nodepool1-18558189-0 10.240.0.4...
Suppose you have private & public SSH key on your side and you want to SSH to a node namedaks-nodepool1-18558189-0, execute the plugin with options like this:
- usernaem:
myuser - identity:
~/.ssh/id_rsa_k8s - pubkey:
~/.ssh/id_rsa_k8s.pub)
$ kubectl ssh-jump aks-nodepool1-18558189-0 \ -u myuser -i~/.ssh/id_rsa_k8s -p~/.ssh/id_rsa_k8s.pub
[NOTE] you can try SSH into a node using node IP address (
Internal-IP) instead ofHostname
As explained in usage secion,username,identity,pubkey options will be cached, therefore you can omit these options afterward.
$ kubectl ssh-jump aks-nodepool1-18558189-0
You can pass the commands to run in the destination node like this (Suppose thatusername,identity,pubkey options are cached):
echo"uname -a"| kubectl ssh-jump aks-nodepool1-18558189-0(Output)Linux aks-nodepool1-18558189-0 4.15.0-1035-azure#36~16.04.1-Ubuntu SMP Fri Nov 30 15:25:49 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
You can pass commands byargs
kubectl ssh-jump aks-nodepool1-18558189-0 --args"uname -a"(Output)Linux aks-nodepool1-18558189-0 4.15.0-1035-azure#36~16.04.1-Ubuntu SMP Fri Nov 30 15:25:49 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
You can clean up sshjump pod at the end of the command with--cleanup-jump option, otherwise, the sshjump pod stay running by default.
$ kubectl ssh-jump aks-nodepool1-18558189-0 \ -u myuser -i~/.ssh/id_rsa_k8s -p~/.ssh/id_rsa_k8s.pub \ --cleanup-jump
You can clean up ssh-agent at the end of the command with--cleanup-agent option, otherwise, the ssh-agent process stay running once it's started.
$ kubectl ssh-jump aks-nodepool1-18558189-0 \ -u myuser -i~/.ssh/id_rsa_k8s -p~/.ssh/id_rsa_k8s.pub \ --cleanup-agent
You can skip startingssh-agent by giving--skip-agent. This is actually a case where you already have ssh-agent managed. Or you can start new ssh-agent and add an identity key to the ssh-agent like this:
# Start ssh-agent manually$eval`ssh-agent`# Add an arbitrary private key, give the path of the key file as an argument to ssh-add$ ssh-add~/.ssh/id_rsa_k8s# Then, run the plugin with --skip-agent$ kubectl ssh-jump aks-nodepool1-18558189-0 \ -u myuser -i~/.ssh/id_rsa_k8s -p~/.ssh/id_rsa_k8s.pub \ --skip-agent# At the end, run this if you want to kill the current agent$ ssh-agent -k
From v0.4.0, the plugin supports PEM (Privacy Enhanced Mail) scenario where you create key-pair but you only have .pem / private key (downloaded from AWS, for example) and you don't have the public key on your side.
Suppose you've already downloaded a pem file and you want to ssh to your EKS worker node (EC2) namedip-10-173-62-96.ap-northeast-1.compute.internal using the pem, execute the plugin with options like this:
- usernaem:
ec2-user - identity:
~/.ssh/mykey.pem
$ kubectl ssh-jump -u ec2-user -i~/.ssh/mykey.pem ip-10-173-62-96.ap-northeast-1.compute.internalBug reports and pull requests are welcome on GitHub athttps://github.com/yokawasa/kubectl-plugin-ssh-jump
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A kubectl plugin to access nodes or remote services using a SSH jump Pod
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