Fixes#125
### Motivation
The default images in the values.yaml are in docker hub. This PR allows us to provide image pull secrets for the containers which will allow us to get around Docker Hub's rate limiting if the nodes are not logged into Docker Hub.
### Modifications
Added a new template to generate `imagePullSecrets`, and included them in the deployments and statefulsets. This will only add them if they are specified under `images.imagePullSecrets`
### Verifying this change
- [] Make sure that the change passes the CI checks.
Fixes #<xyz>
### Motivation
would be nice to have this option here so people can run admin commands against the prometheus.
### Modifications
added a new value and modified the deployment, taken from the official prom helm.
### Verifying this change
- [ ] Make sure that the change passes the CI checks.
Fixes#116
### Motivation
Theres indentation issues for the `checksum/config` annotation in these templates, which would either fail linting or not apply at all in some situations.
### Modifications
I've added indentation at the specified places such that this isn't an issue anymore.
### Verifying this change
- [ ] Make sure that the change passes the CI checks.
Fixes#71
### Motivation
Pods are not restarting when config maps are changed after changing values.yaml file, so they need to be restarted manually in order to pick up new values from config map.
### Modifications
As I mentioned `restartPodsOnConfigMapChange` flag for each component is added in values.yaml file whether to restart pods on configmap change or not, default is `false`.
In statefulset templates for each component is added part which is adding annotation that contains hash of corresponding configmap if `restartPodsOnConfigMapChange` is `true`, which will cause pods to restart if corresponding configmap has been changed (https://helm.sh/docs/howto/charts_tips_and_tricks/#automatically-roll-deployments).
### Verifying this change
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It remains possible to override the current release namespace by setting
the `namespace` value though this may lead to having the helm metadata
and the pulsar components in different namespaces
Fixes#66
### Motivation
Trying to deploy the chart in a namespace using the usual helm pattern fails for example
```
kubectl create ns pulsartest
helm upgrade --install pulsar -n pulsartest apache/pulsar
Error: namespaces "pulsar" not found
```
fixing that while keeping the helm metadata and the deployed objects in the same namespace requires declaring the namespace twice
```
kubectl create ns pulsartest
helm upgrade --install pulsar -n pulsartest apache/pulsar --set namespace=pulsartest
Error: namespaces "pulsar" not found
```
This is needlessly confusing for newcomers who follow the helm documentation and is contrary to helm best practices.
### Modifications
I changed the chart to use the context namespace `.Release.Namespace` by default while preserving the ability to override that by explicitly providing a namespace on the commande line, with the this modification both examples behave as expected
### Verifying this change
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### Motivation
As seen below, there is a fix for one of the Grafana dashboards that are currently broken in this project (available since version 0.0.5):
- [The Pulsar-topics metrics can't load in Grafana](https://github.com/streamnative/charts/issues/49)
Additionally, upgrading Prometheus to the latest version improves performance as seen here: https://prometheus.io/blog/2017/11/08/announcing-prometheus-2-0
### Modifications
Bring Docker images to their most up-to-date version (streamnative/apache-pulsar-grafana-dashboard-k8s:0.0.6, prom/prometheus:v2.17.2) to fix the following issues:
- https://github.com/streamnative/charts/issues/49 <- fixes Pulsar-topics metrics failure to load
- https://github.com/prometheus/prometheus/pull/2859 <- prevent escalation vulnerabilities by defaulting to the ```nobody``` user
**Note**: upgrading to the latest version of Prometheus (currently v2.17.2) caused the pod to fail with the following error: ```open /prometheus/queries.active: permission denied```. In order to fix this issue I followed the instructions from these 2 comments:
- [Permission denied UID/GID solution](https://github.com/prometheus/prometheus/issues/5976#issuecomment-532942295)
- [Unable to create mmap-ed active query log securityContext fix](https://github.com/aws/eks-charts/issues/21#issuecomment-607031756)
### Verifying this change
- [x] Make sure that the change passes the CI checks.
