Amazon Linux 2 support

[majormoses]

I'd guess there are some things that we need to adjust to properly support amazon2 as this moves to systemd which is the thing that I expect will break things, there probably needs to be some omnibus work done first but we need to consider all the times we check platform family and similar here.

https://aws.amazon.com/about-aws/whats-new/2017/12/introducing-amazon-linux-2

[tas50]

You can check node['init_package'] within your platform checks. On any system with systemd it'll be 'systemd'.

[majormoses]

That has been super unreliable on the whole, this is partially due to a couple of reasons:

• supporting multiple init systems: Ubuntu 14.04 has systemd, upstart, and sys-v installed but the default on 14.04 is sys-v
• related to above: there is no standard way to determine what pid 1 really is.

See: https://github.com/chef/ohai/issues/917

[adhodgson1]

Not related to Sensu necessairily but I have checked several Chef cookbooks on AWS Linux2 and several of them brake due to the platform check. I haven't had time to look into this further but just ran a few tests. Currently I am getting stuff like this firing:

if node['platform_version'].to_i <= 5

This currently equates to true on AWS Linux2 so any cookbook that uses similar (and there seems to be quite a few) currently brakes.

Andrew.

[majormoses]

resolved in #614