SSH Recipes

ssh-config-basic

# Example ssh config file. Usually located in ~/.ssh/config (user) or /etc/ssh/ssh_config (system)
# This works on both linux and MacOS

# Basic ssh commands converted to ssh/config file format



# Simplest format
# Run with: "ssh blog" => (equivalent to: "ssh ubuntu@example.com" and  "ssh -i ~/.ssh/id_rsa -p 22 ubuntu@example.com")
Host blog
	User ubuntu
	HostName example.com


# Setting more options
# Run with: "ssh secure_blog" => (equivalent to: "ssh -p 12345 -i ~/.ssh/identity_file_that_is_not-id_rsa ubuntu@example.com")
Host secure_blog
	User ubuntu
	HostName example.com
	Port 12345
	IdentityFile ~/.ssh/identity_file_that_is_not-id_rsa

ssh-config-patterns

# Example ssh config file. Usually located in ~/.ssh/config (user) or /etc/ssh/ssh_config (system)
# This works on both linux and MacOS

# Using patterns in ssh/config file.
# This removes a lot of unnecessary repetition while writing this file.



# Subdomain patterns using wildcards
# Run with "ssh www.example.com" => (equivalent to: "ssh ubuntu@www.example.com")
# Run with "ssh blog.example.com" => (equivalent to: "ssh ubuntu@blog.example.com")
Host *.example.com
	HostName %h
	User ubuntu


# Subdomain patterns with "?" (matches one character)
# Run with "ssh box1" => (equivalent to: "ssh ubuntu@box1.example.com")
# Run with "ssh boxZ" => (equivalent to: "ssh ubuntu@boxZ.example.com")
Host box?
	HostName %h.example.com
	User ubuntu

# Multiple patterns
# Run with "ssh box3" => (equivalent to: "ssh ubuntu@box3.example.com")
# Run with "ssh cluster01" => (equivalent to: "ssh ubuntu@cluster01.example.com")
# Run with "ssh cluster99" => (equivalent to: "ssh ubuntu@cluster99.example.com")
Host box? cluster??
	HostName %h.example.com
	User ubuntu


# Exclusion Patterns
# Prepend any pattern with "!" and it will be negated
# Run with "ssh box1" => (equivalent to: "ssh ubuntu@box1.example.com")
# Run with "ssh box0" will generate an error: "ssh: Could not resolve hostname box0: nodename nor servname provided, or not known"
Host box? !box0
	HostName %h.example.com
	User ubuntu


# Cascaded patterns: Patterns can be cascaded as follows
# Below options are "defaults" for all subdomains of example.com
Host *.example.com
	HostName %h.example.com
	User ubuntu

Host box?.example.com
  # Run with "ssh box1.example.com" => (equivalent to: "ssh centos@box1.example.com")
  User centos
  
Host cluster??
  # Run with "ssh cluster99" => (equivalent to: "ssh -i  ~/.ssh/cluster.id_rsa ubuntu@cluster99.example.com")
	IdentityFile ~/.ssh/cluster.id_rsa

# More on patterns under "Patterns" section here: https://linux.die.net/man/5/ssh_config

ssh-config-proxy

# Example ssh config file. Usually located in ~/.ssh/config (user) or /etc/ssh/ssh_config (system)
# This works on both linux and MacOS

# Jumpboxes/Proxies/Firewalls can be in between servers. (e.g. localbox -> proxy -> example.com)
# Login through proxy
# First define the proxy connection
Host jumpbox
  HostName myproxy.example.com
  User ubuntu



# Login to a private machine (behind a jumpbox)
# Run with "ssh jb.private01" => (equivalent to: "ssh jumpbox -tt ssh centos@private01")
#   => Also equivilant to ssh ubuntu@myproxy.example.com -tt ssh centos@private01
# Note that User/HostName are used by jumpbox's connection, not your local machine
Host jb.private01
	HostName private01
	User centos
	ProxyCommand ssh jumpbox -W %h:%p



# Login to multiple private machines (behind a jumpbox), with a common prefix
# Run with "ssh jb.private99" => (equivalent to: "ssh jumpbox -tt ssh centos@private99")
# $(echo %h | cut -d. -f1- ) takes the hostname "jb.private99", splits it by "." delimiter, then captures all the fields starting second
Host jb.*
	User centos
	ProxyCommand ssh jumpbox -W $(echo %h | cut -d. -f2- ):%p



# Login to a private machine with a non-default key
# You need "nc" to be installed on the jumpbox machine to be able to do this
# Run with "ssh confidential" => (equivalent to: "ssh jumpbox -tt ssh -i ~/non_default_key centos@private01")
Host confidential
	HostName confidential
	User centos
  ProxyCommand ssh -o 'ForwardAgent yes' jumpbox 'ssh-add path/to/keyfile && nc %h %p'



# Port-forwarding (using tunnels)
# Tunnel with "ssh -fN jumpbox_tunnels" (then you can access private:9200 as localhost:9401)
Host jumpbox_tunnels
  HostName myproxy.example.com
  User ubuntu
  LocalForward 9401 private01:9200
  LocalForward 9402 private02:9200
  LocalForward 9403 private03:9200

Thanks!