Protect against case where an alloc has no services and avoid
dereferencing null.
Here, we ensure that the model and test serializers mimic the API by
having nil TaskGroup.Services instead of an empty array.
Currently, using a Volume in a job uses the following configuration:
```
volume "alias-name" {
type = "volume-type"
read_only = true
config {
source = "host_volume_name"
}
}
```
This commit migrates to the following:
```
volume "alias-name" {
type = "volume-type"
source = "host_volume_name"
read_only = true
}
```
The original design was based due to being uncertain about the future of storage
plugins, and to allow maxium flexibility.
However, this causes a few issues, namely:
- We frequently need to parse this configuration during submission,
scheduling, and mounting
- It complicates the configuration from and end users perspective
- It complicates the ability to do validation
As we understand the problem space of CSI a little more, it has become
clear that we won't need the `source` to be in config, as it will be
used in the majority of cases:
- Host Volumes: Always need a source
- Preallocated CSI Volumes: Always needs a source from a volume or claim name
- Dynamic Persistent CSI Volumes*: Always needs a source to attach the volumes
to for managing upgrades and to avoid dangling.
- Dynamic Ephemeral CSI Volumes*: Less thought out, but `source` will probably point
to the plugin name, and a `config` block will
allow you to pass meta to the plugin. Or will
point to a pre-configured ephemeral config.
*If implemented
The new design simplifies this by merging the source into the volume
stanza to solve the above issues with usability, performance, and error
handling.
The default ulimit for open files on macOS is really small (256),
which leads to "too many open files" errors during plugin launches if
you're running unit tests in `drivers/docker`. Recommend setting
`ulimit -n 1024`.
- In script checks, ensure we're running `Exec` against the new running
allocation and not the earlier stopped one.
- In script checks, allow `Exec` calls to error due to lack of pty when
we use the exec to kill the task.
- In `utils.go/RegisterAllocs`, force query for allocations to wait on
wait index returned by registration call.
On macOS, `os.TempDir` returns a symlinked path under `/var` which is
outside of the directories shared into the VM used for Docker, and
that fails tests using Docker that need that mount. If we expand the
symlink to get the real path in `/private`, we're in the shared
folders and can safely mount them.
When multiple developers are working on e2e testing, it helps to be
able to identify which infrastructure belongs to which Nomad SHA and
which developer. This adds tags to the EC2 instances.
