* Add collect command and remote host collectors
Adds the ability to run a host collector on a set of remote k8s nodes.
Target nodes can be filtered using the --selector flag, with the same
syntax as kubectl. Existing flags for --collector-image,
--collector-pullpolicy and --request-timeout are used. To run on a
specified node, --selector="kubernetes.io/hostname=kind-worker2" could
be used.
The collect command is used by the remote collector to output the
results using a "raw" format, which uses the filename as the key, and
the value the output as a escaped json string. When run manually it
defaults to fully decoded json. The existing block devices,
ipv4interfaces and services host collectors don't decode properly - the
fix is to convert their slice output to a map (fix not included as
unsure what depends on the existing format).
The collect command is also useful for troubleshooting preflight issues.
Examples are included to show remote collector usage.
```
bin/collect --collector-image=croomes/troubleshoot:latest examples/collect/remote/memory.yaml --namespace test
{
"kind-control-plane": {
"system/memory.json": {
"total": 1304207360
}
},
"kind-worker": {
"system/memory.json": {
"total": 1695780864
}
},
"kind-worker2": {
"system/memory.json": {
"total": 1726353408
}
}
}
```
The preflight command has been updated to run remote collectors. To run
a host collector remotely it must be specified in the spec as a
`remoteCollector`:
```
apiVersion: troubleshoot.sh/v1beta2
kind: HostPreflight
metadata:
name: memory
spec:
remoteCollectors:
- memory:
collectorName: memory
analyzers:
- memory:
outcomes:
- fail:
when: "< 8Gi"
message: At least 8Gi of memory is required
- warn:
when: "< 32Gi"
message: At least 32Gi of memory is recommended
- pass:
message: The system has as sufficient memory
```
Results for each node are analyzed separately, with the node name
appended to the title:
```
bin/preflight --interactive=false --collector-image=croomes/troubleshoot:latest examples/preflight/remote/memory.yaml --format=json
{memory running 0 1}
{memory completed 1 1}
{
"fail": [
{
"title": "Amount of Memory (kind-worker2)",
"message": "At least 8Gi of memory is required"
},
{
"title": "Amount of Memory (kind-worker)",
"message": "At least 8Gi of memory is required"
},
{
"title": "Amount of Memory (kind-control-plane)",
"message": "At least 8Gi of memory is required"
}
]
}
```
Also added a host collector to allow preflight checks of required kernel
modules, which is the main driver for this change.
