docs: add available configuration options for rollouts controller.

Refs: argoproj#1914
Signed-off-by: Celal Öner <[email protected]>

docs/installation.md

@@ -26,6 +26,73 @@ This will create a new namespace, `argo-rollouts`, where Argo Rollouts controlle
 You can find released container images of the controller at [Quay.io](https://quay.io/repository/argoproj/argo-rollouts?tab=tags). There are also old releases
 at Dockerhub, but since the introduction of rate limiting, the Argo project has moved to Quay.
 
+### Configuration Options
+
+Argo Rollouts Controller is a Kubernetes controller that continuously manages the Rollout resources in the cluster. This command runs Argo Rollouts Controller in the foreground, and it can be configured by following options.
+
+```
+rollouts-controller [flags]
+```
+
+```
+      --alb-ingress-classes stringArray           Defines all the ingress class annotations that the alb ingress controller operates on. Defaults to alb (default [alb])
+      --ambassador-api-version string             Set the Ambassador apiVersion that controller should look when manipulating Ambassador Mappings. (default "getambassador.io/v2")
+      --analysis-threads int                      Set the number of worker threads for the Experiment controller (default 30)
+      --appmesh-crd-version string                Set the default AppMesh CRD Version that controller uses when manipulating resources. (default "v1beta2")
+      --as string                                 Username to impersonate for the operation
+      --as-group stringArray                      Group to impersonate for the operation, this flag can be repeated to specify multiple groups.
+      --as-uid string                             UID to impersonate for the operation
+      --aws-verify-target-group                   Verify ALB target group before progressing through steps (requires AWS privileges)
+      --burst int                                 Maximum burst for throttle. (default 80)
+      --certificate-authority string              Path to a cert file for the certificate authority
+      --client-certificate string                 Path to a client certificate file for TLS
+      --client-key string                         Path to a client key file for TLS
+      --cluster string                            The name of the kubeconfig cluster to use
+      --context string                            The name of the kubeconfig context to use
+      --experiment-threads int                    Set the number of worker threads for the Experiment controller (default 10)
+      --healthzPort int                           Set the port the healthz endpoint should be exposed over (default 8080)
+  -h, --help                                      help for argo-rollouts
+      --ingress-api-version string                Set the Ingress apiVersion that the controller should use.
+      --ingress-threads int                       Set the number of worker threads for the Ingress controller (default 10)
+      --insecure-skip-tls-verify                  If true, the server's certificate will not be checked for validity. This will make your HTTPS connections insecure
+      --instance-id string                        Indicates which argo rollout objects the controller should operate on
+      --istio-api-version string                  Set the default Istio apiVersion that controller should look when manipulating VirtualServices. (default "v1alpha3")
+      --kloglevel int                             Set the klog logging level
+      --kubeconfig string                         Path to a kube config. Only required if out-of-cluster
+      --leader-elect                              If true, controller will perform leader election between instances to ensure no more than one instance of controller operates at a time (default true)
+      --leader-election-lease-duration duration   The duration that non-leader candidates will wait after observing a leadership renewal until attempting to acquire leadership of a led but unrenewed leader slot. This is effectively the maximum duration that a leader can be stopped before it is replaced by another candidate. This is only applicable if leader election is enabled. (default 15s)
+      --leader-election-renew-deadline duration   The interval between attempts by the acting master to renew a leadership slot before it stops leading. This must be less than or equal to the lease duration. This is only applicable if leader election is enabled. (default 10s)
+      --leader-election-retry-period duration     The duration the clients should wait between attempting acquisition and renewal of a leadership. This is only applicable if leader election is enabled. (default 2s)
+      --logformat string                          Set the logging format. One of: text|json
+      --loglevel string                           Set the logging level. One of: debug|info|warn|error (default "info")
+      --metricsport int                           Set the port the metrics endpoint should be exposed over (default 8090)
+  -n, --namespace string                          If present, the namespace scope for this CLI request
+      --namespaced                                runs controller in namespaced mode (does not require cluster RBAC)
+      --nginx-ingress-classes stringArray         Defines all the ingress class annotations that the nginx ingress controller operates on. Defaults to nginx (default [nginx])
+      --password string                           Password for basic authentication to the API server
+      --qps float32                               Maximum QPS (queries per second) to the K8s API server (default 40)
+      --request-timeout string                    The length of time to wait before giving up on a single server request. Non-zero values should contain a corresponding time unit (e.g. 1s, 2m, 3h). A value of zero means don't timeout requests. (default "0")
+      --rollout-resync int                        Time period in seconds for rollouts resync. (default 900)
+      --rollout-threads int                       Set the number of worker threads for the Rollout controller (default 10)
+      --server string                             The address and port of the Kubernetes API server
+      --service-threads int                       Set the number of worker threads for the Service controller (default 10)
+      --tls-server-name string                    If provided, this name will be used to validate server certificate. If this is not provided, hostname used to contact the server is used.
+      --token string                              Bearer token for authentication to the API server
+      --traffic-split-api-version string          Set the default TrafficSplit apiVersion that controller uses when creating TrafficSplits. (default "v1alpha1")
+      --user string                               The name of the kubeconfig user to use
+      --username string                           Username for basic authentication to the API server
+      --version                                   Print version
+```
+
+For instance, logging format can be easily set as `json` in Argo Rollouts Controller Deployment as follows:
+
+````yaml
+      containers:
+      - image: "image: quay.io/argoproj/argo-rollouts:v1.2.0"
+        args:
+        - --logformat=json
+````
+
 ## Kubectl Plugin Installation
 
 The kubectl plugin is optional, but is convenient for managing and visualizing rollouts from the