Ssh – Configure SSH credentials per environment

ansiblessh

I'm trying to figure out how to configure the SSH credentials separately for a production and staging environment with Ansible. I understand that you can configure the server IP addresses and hostnames separately using different inventory files by passing the -i or --inventory-file argument to the ansible-playbook command. However, I see no such option for ansible.cfg. Currently, the credentials live in /etc/ansible/ansible.cfg as:

[defaults]
private_key_file=/home/caleb/.ssh/staging_key.pem
remote_user=ubuntu
sudo_user=root
gathering=explicit

How can I configure multiple SSH credentials, one for production and one for staging?

Best Answer

Seems like my first answer was not entirely correct. While of course it is possible to solve it in your .ssh/config like described below, it seems as well to be possible with Ansibles Behavioral Inventory Parameters.

You should (according to docs) be able to define the keyfile and the user in your inventory, either per host or per group.

Definition per group:

[some_hosts]
host1.foo
host2.foo

[some_hosts:vars]
ansible_ssh_user=ubuntu
ansible_ssh_private_key_file=/home/caleb/.ssh/staging_key.pem

Definition per host:

[some_hosts]
host1.foo     ansible_ssh_user=ubuntu          ansible_ssh_private_key_file=/home/caleb/.ssh/staging_key.pem
host2.foo     ansible_ssh_user=another_user    ansible_ssh_private_key_file=/home/caleb/.ssh/production_key.pem

But you can define multiple host groups already in your .ssh/config and each group can have their separate settings regarding key and user.

Here is a quick example

#Example with a wildcard
Host *.foo.com
  user ubuntu
  IdentityFile /home/caleb/.ssh/staging_key.pem

#Example with multiple hostnames
Host hostname.one hostname.two hostname.three
  user other_user
  IdentityFile /home/caleb/.ssh/production_key.pem

As well you could define a default and override it later with more detailed settings.

Host *
  user defaut_username

Host somehost
  user special_username

Related Solutions

Security – How to implement ansible with per-host passwords, securely

You've certainly done your research...

From all of my experience with ansible what you're looking to accomplish, isn't supported. As you mentioned, ansible states that it does not require passwordless sudo, and you are correct, it does not. But I have yet to see any method of using multiple sudo passwords within ansible, without of course running multiple configs.

So, I can't offer the exact solution you are looking for, but you did ask...

"So... how are people using Ansible in situations like these? Setting NOPASSWD in /etc/sudoers, reusing password across hosts or enabling root SSH login all seem rather drastic reductions in security."

I can give you one view on that. My use case is 1k nodes in multiple data centers supporting a global SaaS firm in which I have to design/implement some insanely tight security controls due to the nature of our business. Security is always balancing act, more usability less security, this process is no different if you are running 10 servers or 1,000 or 100,000.

You are absolutely correct not to use root logins either via password or ssh keys. In fact, root login should be disabled entirely if the servers have a network cable plugged into them.

Lets talk about password reuse, in a large enterprise, is it reasonable to ask sysadmins to have different passwords on each node? for a couple nodes, perhaps, but my admins/engineers would mutiny if they had to have different passwords on 1000 nodes. Implementing that would be near impossible as well, each user would have to store there own passwords somewhere, hopefully a keypass, not a spreadsheet. And every time you put a password in a location where it can be pulled out in plain text, you have greatly decreased your security. I would much rather them know, by heart, one or two really strong passwords than have to consult a keypass file every time they needed to log into or invoke sudo on a machine.

So password resuse and standardization is something that is completely acceptable and standard even in a secure environment. Otherwise ldap, keystone, and other directory services wouldn't need to exist.

When we move to automated users, ssh keys work great to get you in, but you still need to get through sudo. Your choices are a standardized password for the automated user (which is acceptable in many cases) or to enable NOPASSWD as you've pointed out. Most automated users only execute a few commands, so it's quite possible and certainly desirable to enable NOPASSWD, but only for pre-approved commands. I'd suggest using your configuration management (ansible in this case) to manage your sudoers file so that you can easily update the password-less commands list.

Now, there are some steps you can take once you start scaling to further isolate risk. While we have 1000 or so nodes, not all of them are 'production' servers, some are test environments, etc. Not all admins can access production servers, those than can though use their same SSO user/pass|key as they would elsewhere. But automated users are a bit more secure, for instance an automated tool that non-production admins can access has a user & credentials that cannot be used in production. If you want to launch ansible on all nodes, you'd have to do it in two batches, once for non-production and once for production.

We also use puppet though, since it's an enforcing configuration management tool, so most changes to all environments would get pushed out through it.

Obviously, if that feature request you cited gets reopened/completed, what you're looking to do would be entirely supported. Even then though, security is a process of risk assessment and compromise. If you only have a few nodes that you can remember the passwords for without resorting to a post-it note, separate passwords would be slightly more secure. But for most of us, it's not a feasible option.

How to set default Ansible username/password for SSH connection

You can add following section to your inventory file:

[all:vars]
ansible_connection=ssh
ansible_user=vagrant
ansible_ssh_pass=vagrant

Note: Before Ansible 2.0 ansible_user was ansible_ssh_user.

Best Answer

Related Solutions

Security – How to implement ansible with per-host passwords, securely

How to set default Ansible username/password for SSH connection

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