This changeset adds volumes but does not mount them to instances so
that we can test the mounting ("staging") via CSI plugins. The CSI
plugins themselves will be installed as Nomad jobs.
In order to ensure we can always mount the EFS volume, this changeset
pins the deployment of the cluster to a specific subnet. In future
work we should spread the cluster out among several AZs and test that
behavior explicitly.
This changeset is part of the work to improve our E2E provisioning
process to allow our upgrade tests:
* Move more of the setup into the AMI image creation so it's a little
more obvious to provisioning config authors which bits are essential
to deploying a specific version of Nomad.
* Make the service file update do a systemd daemon-reload so that we
can update an already-running cluster with the same script we use to
deploy it initially.
Update the Consul and Vault configs to take advantage of their
included `go-sockaddr` library for getting the IP addresses we need in
a portable way. This particularly avoids problems with "predictable"
interface names provided by systemd.
Also adds the `sockaddr` binary to the Packer build so we can use it
in our provisioning scripts.
Make a clear split between Packer and Terraform provisioning steps:
the scripts in the `packer/linux` directory are run when we build the
AMI whereas the stuff in shared are run at Terraform provisioning time.
Merging all runtime provisioning scripts into a single script for each
of server/client solves the following:
* Userdata scripts can't take arguments, they can only be templated
and that means we have to do TF escaping in bash/powershell scripts.
* TF provisioning scripts race with userdata scripts.
