hostctl - A ssh loop on steroids

Convenient management and execution of command on groups of hosts : A ssh loop on sterioids I created this tool more than one decade ago, because existing tools suck. (Cluster Shell, Bolt, ... and probably because of NIH)

Install and use

1. Download ar current release from the releases page
2. Extract the archive

   cd ${INSTALL_DIR?The installation base directory}
   tar xvf hostctl-v0.9.11.tar.gz

3. Add the tool to a directory which is in your PATH search-scope

   cd ${INSTALL_DIR?The installation base directory}/hostctl
   ln -snf $PWD/hostctl ~/bin/hostctl

4. Create directories

   mkdir -p ~/.hostctl/repices
   

5. Configure your environments: (See also "EXAMPLES" section)

   echo << 'EOF'
   #<groupname> : <host>, <host>, ...
   web2 :  barfoo-l01-ap01, barfoo-l01-ap02, barfoo-l01-ap03, barfoo-l01-ap04, barfoo-l01-ap05, barfoo-l01-ap06
   db2 :  barfoo-l01-db01, barfoo-l01-db02, barfoo-l01-db03
   EOF 
   

6. Add shell completion to your shell init (~/.bashrc, ~/.zshrc)

   source ${INSTALL_DIR?The installation base directory}/hostctl_$( basename $SHELL)_completion.sh
   

7. Configure SSH
   • Use the "ssh-agent"
   • Activate ssh agent forwarding (openssh: ForwardAgent yes) on your desktop
     ssh client and all systems you want to use "hostctl"
   • Activate ssh agent-forwarding (openssh: AllowAgentForwarding yes, this should be the default value) on your ssh servers

Invoke hostctl to execute commands or scripts on the specified hosts.

Develop

1. Install software prerequisites:

   sudo apt-get install rustc ssh screen 
   

2. Build it and add it to a directory which is in your PATH search-scope

   cd ${INSTALL_DIR?The installation base directory}/hostctl
   git clone https://github.com/scoopex/hostctl.git hostctl
   cd hostctl
   cargo build --release
   ln -snf ${INSTALL_DIR?The installation base directory}/hostctl/target/release/hostctl ~/bin/hostctl
   

3. Build completions

   target/release/hostctl generate-completions bash > misc/hostctl_bash_completion.sh
   target/release/hostctl generate-completions zsh > misc/hostctl_zsh_completion.sh
   target/release/hostctl generate-completions fish > misc/hostctl_fish_completion.sh
   echo "source $INSTALLDIR/hostctl/misc/hostctl_bash_completion.sh" >> .bashrc
   exec bash
   

4. Execute step 4 and later in the previous section

Help Output

(output of "hostctl --help")

$ hostctl --help

convenient management and execution of command on groups of hosts

Usage: hostctl [OPTIONS] [ITEMS]...

Arguments:
  [ITEMS]...  Groups or nodes for the iteration

Options:
  -c, --command <COMMAND>      Command to execute. A ssh login is performed on the specified hosts and the specified command is executed on the remotehost [default: ]
  -e, --execute-local          Execute as local command and add hostname to the command (Hostname will be appended to the command, or inserted where 'HOST' string is located in the string
  -r, --recipe <RECIPE>        Recipe to execute. A recipe is a shellscript which defines recurring administration tasks. Recipes can be stored in $HOME/.hostctl/recipe/ or <hostctl-installation-path>/recipe/ and can be called by their basename. Alternatively, recipes can be called be their fully qualified path [default: ]
  -n, --nodes                  Specify hosts instead of groups
  -s, --show                   show group(s)
  -a, --array                  Output an array list od nodes
  -j, --json                   output hosts in json format
  -d, --debug                  debug mode
  -f, --forcecolor             disable automatic detection of interactive usage and output colors always
  -q, --quiet                  reduce output, useful for aggregating output of multiple hosts
  -b, --batchmode              
  -i, --inscreen <INSCREEN>    start command/script screen session [default: ]
  -o, --optssh <OPTSSH>        Add the arguments to the ssh command [default: ]
  -l, --login                  
      --sudo                   
  -t, --term                   
  -w, --wait <WAIT>            wait a specified number of seconds before continuing at next host [default: 0]
  -p, --prompt                 ask after every execution, if hostctl should continue, retry, execute a shell or quit
  -m, --makeselection          raise a prompt before each host which provides the possibility to confirm or skip the host or quit execution
      --log-level <LOG_LEVEL>  The log level [default: info]
  -h, --help                   Print help
  -V, --version                Print version


    EXAMPLES

    Show disk usage on all systems which belong to group 'foobar'
        "hostctl -c 'df -h' foobar"

    Show disk usage on all systems which belong to group 'foobar', ask after
    every node what to do next
        "hostctl -p -c 'df -h' foobar"

    Execute ncurses application 'top' on all systems which belong to group
    'foobar' using a pseudo tty
        "hostctl -t -c 'top' foobar"

    Copy files using rsync to a remotehost by replacing the string HOST with the
    current hostname of the systems
        "hostctl -e -c 'rsync -avP /tmp/foo HOST:/tmp/bar' foobar"

    Execute script/recipe 'apache_status' on all systems which belong to
    group 'foobar' (shortcut or explictit path)
        "hostctl -r apache_status foobar"
        "hostctl -r /foo/bar/baz/apache_status foobar"

    Login sequentially on all hosts which belong to group 'foobar'
        "hostctl -l foobar"

    Start a screen session with 'top' on all systems which belong to group
    'foobar'
        "hostctl -c 'top' --inscreen my-magic-screen foobar"
        "screen -x my-magic-screen"

    ENVIRONMENT VARIABLES

    HOSTCTL_CONFIG
        Define a alternate configuration location directory

        Default search order: ~/.hostctl/hostctl.conf, <HOSTCTL BINARY DIRECTORY>/hostctl.conf

Configuration file format (hostctl.conf):

#<groupname> : <host>, <host>, ...
web2 :  barfoo-l01-ap01, barfoo-l01-ap02, barfoo-l01-ap03, barfoo-l01-ap04, barfoo-l01-ap05, barfoo-l01-ap06
db2 :  barfoo-l01-db01, barfoo-l01-db02, barfoo-l01-db03

• Hostgroup web2 is only visible/usable on host jump-barfoo
• Hostgroup db2 is only visible/usable on host jump-barfoo

Missing features

• Implement completion of hosts and groups
• cluster shell mode with "--inscreen" : send STDIN of a master terminal to all screens
• packaging for rpm and deb
• Manual sorting of nodes
• Health check cmd for finishing the node

Licence and Authors

Additional authors are very welcome - just submit your patches as pull requests.

• Marc Schoechlin [email protected]