rcse

README

RCSE (Run Command Somewhere Else)

rcse is meant to be a simple tool for remote machine automation written in Go, utilizing only SSH, with no agent or extra packages to install on any remote machines.

The program has subcommands, e.g. shell and script, and those will dictate what actions get performed.

Running a single command

Running rcse shell -c "ls -la" -i <inventory_file> would run "ls -la", listing the contents of your user's home directory on each of the hosts in the inventory file. The command should be quoted, and without a user specified, it will use the current local user's ssh keys (id_rsa by default, see --help for more options).

Running a script

The subcommand script allows for a script, from your local machine, to be ran remotely on all hosts in the inventory.

Running this would look like rcse script my_script.sh -i <inventory_file>. All options available to normal commands are available for a script as well, such as running with a different user, or adding forks and failure limits.

Inventory

The inventory file, passed with -i, will supply the list of hosts that the program is ran on. It takes in a plaintext file like the one shown below.

$ cat my_inventory
myhost001.ci.com
myhost[002:010].ci.com
myhost012.ci.com
vmhost001.ci.com
baremetal[01:03].company.location.com

Note that if the hosts are in a contiguous range, you may specify the range with host[start:end]... and rcse will expand it internally like so:

baremetal[01:03].company.location.com

gets expanded to

baremetal01.company.location.com
baremetal02.company.location.com
baremetal03.company.location.com

Authentication

A username, --user, and password, --password, can be specified to execute the commands as a different user. If providing a different user, the program will prompt for password input. You may pass the password explicitly in the command, however that is not recommended.

rcse ... -u root -p and rcse ... -u root -p=CoolPassword are equivalent, but the first one prompts you for password input securely. Note that passing a user without a password flag will still prompt for a password.

If no user is specified, it will use the current user's id_ed25519 found in ~/.ssh/id_ed25519.

Running concurrently

There are options for how many hosts to run on at one time, with the --forks flag. Accompanying it is --failure-limit which will stop and exit the program when that limit is hit. With neither flag set, the forks and failure limit are set to 1 and 1000 respectively, making a default run safe and unopinionated about the failure limit.

At any one time, the program will keep --forks=n amount of executors running. For example, if set to 15, the program will start by executing on 15 hosts concurrently, and then when one finishes, it will pick up the next host to run on, and so on. Contrast this with batching, where the next batch will only start when all hosts in the previous batch have finished. Setting this flag executes on hosts as they are listed in the inventory file, in descending order.

Flags

Each subcommand has its own set of flags relevant to its purpose, as well as global flags available to every command. Please use --help on any command to see options.

Installation

Download

Coming soon

Using Go Modules

git clone git@github.com:nateph/rcse.git
cd rcse && make install

Using $GOPATH

go get github.com/nateph/rcse
cd $GOPATH/src/github.com/nateph/rcse && make install

See Makefile for more options