go-multi-ssh is a small tool used to execute commands on multiple remote machines. The current feature set allows execution on

• multiple remote hosts via SSH
• multiple pods in a kubernetes cluster
• multiple container on a docker host

While the execution via SSH is done by a standalone program both kubernetes and docker integrates as plugin kubectl mexec and docker mexec respectively. Any contents streamed via stdout and stderr will be captured and printed on the local machine again using stdout and stderr.

All three tools share a common set of features

• -c connection test

  Performs a simple connection test and prints all execution targets.

• -l none|block|inline label

  Sets a label type to mark the output with the source execution host.

  • none omits any output labels; the content will be delivered line-by-line regardless of the source
  • block prints a source label once per block; the next label will be printed after a different host sends text to stdout
  • inline prints a source label for every line

• -i index file (defaults to ./ssh_config)

  Specifies an index file containing target hosts. The index file follows the ssh_config file format rules SSH DOCs but has an additional property tag. For any host specified within the index file the systems ssh_config are used for fill missing connection infos. i.e.

  • ~/.ssh/config

    Host *
    IdentityFile ~/.ssh/%h_id_rsa
    
    Host target-host.lan
    User login
    

  • ./ssh_config

    Host target-host.lan
    

  Will lead to a login attempt using [email protected] with the key file ~/.ssh/target-host.lan_id_rsa.

• Tags

  Tags can be used to further narrow down the list of target hosts.

  Use :

  • -t to include

    Includes hosts with the given tag. i.e. mssh -t ubuntu

  • -T to exclude

    Ignores hosts with the given tag. i.e. mssh -T critical

  i.e. given the index file ./ssh_config with

  Host gateway.lan
  
  Host prox-host-1.lan
  Tag ubuntu
  Tag hypervisor
  
  Host ubuntu-1.lan
  Tag ubuntu
  
  Host dns.lan
  Tag ubuntu
  Tag dns
  
  Host dns.iot
  Tag ubuntu
  Tag dns
  
  Host dns.phone
  Tag ubuntu
  Tag dns
  
  Host mqtt-broker.iot
  Tag ubuntu
  
  Host home-assistant.iot
  Tag ubuntu
  
  

  The following calls will target :

  call	gateway.lan	prox-host-1.lan	ubuntu-1.lan	dns.lan	dns.iot	dns.phone	home-assistant.iot	mqtt-broker.iot
  mssh -t ubuntu	☐	☑	☑	☑	☑	☑	☑	☑
  mssh -t ubuntu -T hypervisor	☐	☐	☑	☑	☑	☑	☑	☑
  mssh -t dns	☐	☐	☐	☑	☑	☑	☐	☐
  mssh -t hypervisor	☐	☑	☐	☐	☐	☐	☐	☐
  mssh	☑	☑	☑	☑	☑	☑	☑	☑

• -s selector

  Specifies a selector to select target containers by filtering them using the container label feature. Docker DOCs. i.e. docker mexec -s "com.example.foo=bar"

• -s selector

  Specifies a selector to select target pods by filtering them using the pod label feature. See Kubernetes DOCs. i.e. kubectl mexec -s "app.kubernetes.io/component=database"

• -n namespace

  Specifies the target namespace. i.e. kubectl mexec -n kube-system

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

• Bash
• Gopher
• Kubernetes Pod
• Kubernetes
• Docker
• SSH
• Computer