A ClusterSSH utility (like cssh) for iTerm2.

Opens an iTerm2 Window and connects over ssh to each host specified in the command arguments in a split pane session, with any input typed or pasted in any pane replicated to all panes through iTerm2's 'broadcast' feature.

Installing first time round will take a while - pyobjc is a required package and it compiles a lot of things as it installs. Later installs and upgrades will be much faster as the packages will be cached.

• Install iTerm2 however you like.
• Install csshi:
  $ brew install ilikejam/csshi/csshi
• Enable the iTerm2 Python API at:
  iTerm2 -> Settings... -> General -> Magic
  Select 'Enable Python API' and then 'Require "Automation" permission'.

• Install iTerm2 however you like.
• Install python3 e.g. with homebrew:
  $ brew install python3
• Clone this repo (or just download the 'csshi' file), make the csshi file executable, and maybe copy or link it to somewhere in your $PATH.
• Install the python iterm2 and pyobjc libs through pip:
  $ pip3 install -r requirements.txt
• Enable the iTerm2 Python API at:
  iTerm2 -> Settings... -> General -> Magic
  Select 'Enable Python API' and then 'Require "Automation" permission'.

usage: csshi [-h] [-d] [-k] [-c] [-n] [-l USERNAME] [-p PORT] [-J JUMPHOST]
             [-s SLEEP] [-o OPTIONS] [-b BINARY] [-P PROFILE] [-C COLUMNS |
             -R ROWS]
             (-L | destination ...)

Run multiple ssh connections concurrently in an iTerm2 terminal.

positional arguments:
  destination           [user@]host[:port] ssh connection specification. NB:
                        Square brackets MUST be used around IPv6 IP adresses

options:
  -h, --help            show this help message and exit
  -d, --debug           Turn on debugging
  -k, --kill-inactive   Don't create spacer panes and kill inactive panes
  -c, --caffeinate      Try to keep the Mac awake
  -n, --no-broadcast    Don't enable input broadcast
  -l, --username USERNAME
                        Login username, overridden per-host by specifying
                        'user@host'
  -p, --port PORT       ssh server port, overridden per-host by specifying
                        'host:port'
  -J, --jump JUMPHOST   ProxyJump host specification, like
                        [user@]jumphost[:port]
  -s, --sleep SLEEP     Sleep time in seconds between hosts. Defaults to 0
  -o, --options OPTIONS
                        Raw ssh options string, e.g. '-i ~/.ssh/id_ansible'.
                        Can be specified multiple times.
  -b, --binary BINARY   SSH binary to use. Defaults to 'ssh'
  -P, --profile PROFILE
                        iTerm2 settings Profile to use for csshi window.
                        Defaults to your default Profile.
  -C, --columns COLUMNS
                        Maximum number of columns to use.
  -R, --rows ROWS       Maximum number of rows to use.
  -L, --list-sessions   Print space-separated list of csshi sessions, one line
                        per window

• If running csshi from a different terminal emulator (e.g. Terminal) and -k or -d have been supplied; csshi will dump a stack trace if iTerm2 quits from under us. We still terminate normally, so only a cosmetic issue.
• When running with -k, sessions which exit (e.g. if the hostname is not found) before all of the sessions open may not be closed automatically.

If you have a file listing hostnames to connect to, use xargs:
$ cat file_of_hosts | xargs csshi

Some preferences to optimise for shell density if you find yourself opening a lot of terminals in one csshi session:

• Disable pane menubars:
  iTerm2 -> Settings... -> Appearance -> Panes -> Show per-pane title bar with split panes
  You can still access the menu for each pane with Ctrl-click instead of the menubar burger icon
• Decrease the 'Side' and 'Top & bottom' margins:
  iTerm2 -> Settings... -> Appearance -> Panes
• Add an iTerm2 Profile (iTerm2 -> Settings... -> Profiles) with optimised font size etc, and run csshi with -P <profile name> to use it.

If you are connecting to large numbers of hosts via a single Jumphost, it's advisable to set up multiplexing for the Jumphost:
https://en.wikibooks.org/wiki/OpenSSH/Cookbook/Multiplexing
Also consider raising MaxConnections on that host - the default on OpenSSH is 10.

Throw a PR over, raise an issue, send me an email.