Using Ansible with bastion host

• ansible
• ssh
• bastion

Sometimes due to network configuration or security reasons you can’t access a host directly, but should use intermediate host, so-called bastion host.

I got this setup from this article by Scott Lowe, but ssh.cfg is adjusted so that mentioning exact network mask is not necessary.

ansible.cfg:

[ssh_connection]
# -C enable compression
ssh_args = -C -F ./ssh.cfg

ssh.cfg:

# All hosts
Host *
# Security
ForwardAgent no
# Connection multiplexing
ControlMaster auto
ControlPersist 2m
ControlPath ~/.ssh/ansible-%r@%h:%p
# Connect through bastion hosts
ProxyCommand ssh -W %h:%p bastion1
# Second bastion if first is down
#ProxyCommand ssh -W %h:%p bastion2

# Bastion hosts
Host bastion1
HostName 10.0.0.1
ProxyCommand none

Host bastion2
HostName 10.0.0.2
ProxyCommand none

Somewhere in inventory, to avoid repeating IP addresses twice:

[bastion]
bastion1 ansible_ssh_host=bastion1
bastion2 ansible_ssh_host=bastion2

P.S. Starting from Ansible 2, you can also use ProxyCommand in ansible_ssh_common_args inventory variable: Ansible FAQ.

UPD: stemid85 on Reddit pointed out the way to use a chain of bation hosts:

Host bastion1                                                                                                                   HostName 192.168.1.1

Host bastion2
  HostName 192.168.2.2
  ProxyCommand ssh bastion1 -W %h:%p                                                                                         

Host target
  ProxyCommand ssh bastion2 -W %h:%p                                                                                         

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