operator: disable metrics server by default

[yukinakanaka]

Fixes: #1778

Disable the operator's metrics server by default. If the metrics-bind-address flag is set, it will be enabled.
Regarding Helm, metrics-bind-address is set as 2113 by default when tetragonOperator.prometheus.enabled = true.

operator: Don't start metrics server if Helm value `tetragonOperator.prometheus.enabled` is set to false.

[yukinakanaka]

I confirmed the operator's metrics server is disabled when tetragonOperator.prometheus.enabled = false is set. Here are the test results:

tetragonOperator.prometheus.enabled=false

Parameters for helm

helm upgrade --install --namespace kube-system tetragon ./install/kubernetes/tetragon \
 --set tetragon.image.override=cilium/tetragon:latest \
 --set tetragonOperator.image.override=cilium/tetragon-operator:latest \
  --set tetragon.hostProcPath=/procHost \
  --set tetragonOperator.prometheus.enabled=false

Access the port:2113

The curl failed. That means the operator doesn't listen on the 2113 port.

kubectl debug tetragon-operator-6dd97d997b-94hqv --image=alpine/curl -it -- curl -I localhost:2113/metrics

Defaulting debug container name to debugger-ztx2s.
curl: (7) Failed to connect to localhost port 2113 after 0 ms: Couldn't connect to server

Pod Log

There was no log relating to the metrics server

kubectl logs tetragon-operator-6dd97d997b-94hqv | grep metrics
(no result)

tetragonOperator.prometheus.enabled=true

Parameters for helm

helm upgrade --install --namespace kube-system tetragon ./install/kubernetes/tetragon \
 --set tetragon.image.override=cilium/tetragon:latest \
 --set tetragonOperator.image.override=cilium/tetragon-operator:latest \
  --set tetragon.hostProcPath=/procHost \
  --set tetragonOperator.prometheus.enabled=true

Access the port:2113

The operator returned 200.

kubectl debug tetragon-operator-dfb5b856f-fj566  --image=alpine/curl -it -- curl -I localhost:2113/metrics
Defaulting debug container name to debugger-tj6v8.

HTTP/1.1 200 OK
Content-Type: text/plain; version=0.0.4; charset=utf-8; escaping=values
Date: Thu, 30 May 2024 03:19:28 GMT

Pod Log

There were two lines of logs relating to the metrics server.

kubectl logs tetragon-operator-dfb5b856f-fj566 | grep metrics
Defaulted container "tetragon-operator" out of: tetragon-operator, debugger-j6tmh (ephem), debugger-k9cxr (ephem), debugger-xpv4n (ephem), debugger-qtcv7 (ephem)

time="2024-05-30T02:51:42Z" level=info msg="Starting metrics server" logger=controller-runtime.metrics subsys=operator
time="2024-05-30T02:51:42Z" level=info msg="Serving metrics server" bindAddress=":2113" logger=controller-runtime.metrics secure=false subsys=operator

[lambdanis]

Looks good, thank you!