Switch from supervisord to systemd

[edtan]

Closes #73 by switching to Amazon Linux 2 and changing to systemd.

The vault.service configuration was based off of the configuration listed at the Vault Deployment Guide.

Also, I've updated README.md to indicate that its been updated to Amazon Linux 2, but there is a link to the latest public AMIs. That list will need to be updated with new Amazon Linux 2 AMIs if this PR is accepted.

I've also updated one of the examples to also install pip as it's still required by the terraform-aws-consul modules to install supervisord. I'm looking into updating those modules to use systemd as well, so will remove the reference to pip once I have an PR in for those modules.

update: I submitted hashicorp/terraform-aws-consul#130, but it seems like pip and boto3 is needed for the auth signing script example. Thus, I've updated the PR to install them on Amazon Linux 2 as it seems like they're not already included.

[hashicorp-cla]

All committers have signed the CLA.

[Etiene]

Thanks for the PR! Im going to run the test suite

[brikis98]

This is fantastic, thank you! Let's hope the tests that @Etiene just kicked off pass :)

[edtan]

I've made the suggested changes, and also removed the creation of the /opt/vault/log folder in install-vault.

[Etiene]

Tests are failing to fetch logs (test/vault_helpers.go:134), I'll try to have a look at that, but let me know if you have any insights

[edtan]

It might be because I removed /opt/vault/log in install-vault. I'll get the tests set up on my machine this week and can look into it further.

[Etiene]

Ok, thanks! This error was already happening before the last commit though. It's probably linked to the stdout and stderr path not being updated on tests on test/vault_helpers.go:44

[edtan]

Oh I see, thanks! Since the logs are using journalctl now, I'll look into updating the tests to look there instead.

[edtan]

I've updated the tests so that it writes out the Vault logs to a file. I ran the TestVaultPrivateCluster example locally and it passed for both the Ubuntu and Amazon Linux 2 images. Note that the same logs are in the syslogs, but it might be more convenient for debugging purposes to still have the separate Vault logs.

[brikis98]

@Etiene Could you take over getting this PR passing tests and merged from here?

[Etiene]

Thanks! all tests are passing now. Great PR! 👍