GT-449 Documentation update (#1338)

Author: jwierzbo

docs/design/README.md

@@ -1,5 +1,6 @@
 # ArangoDB operator design documents
 
+- [Architecture change](./arch_change.md)
 - [Constraints](./constraints.md)
 - [Health](./health.md)
 - [Metrics](./metrics.md)
@@ -17,4 +18,7 @@
 - [Operator API](./api.md)
 - [Logging](./logging.md)
 - [Manual Recovery](./recovery.md)
-- [Force rebuild out-synced Shards with broken Merkle Tree](./rebuild_out_synced_shards.md)
+
+## Features
+- [Force rebuild out-synced Shards with broken Merkle Tree](./features/rebuild_out_synced_shards.md)
+- [Failover Leader service](./features/failover_leader_service.md)

docs/design/arch_change.md

@@ -1,8 +1,54 @@
-# Member Architecture change
+# Architecture change
 
-To change manually architecture of specific member, you can use annotation:
+Currently `AMD64` is a default architecture in the operator
+To enable `ARM64` support in operator add following config in kube-arangodb chart:
+
+```bash
+helm upgrade --install kube-arangodb \
+  https://github.com/arangodb/kube-arangodb/releases/download/$VER/kube-arangodb-$VER.tgz \
+  --set "operator.architectures={amd64,arm64}"
+```
+
+## ARM64 ArangoDeployment
+
+`AMD64` is a default architecture in the ArangoDeployment.
+`ARM64` is available since ArangoDB 3.10.0.
+To create `ARM64` ArangoDeployment you need to add `arm64` architecture to the deployment:
+
+```yaml
+apiVersion: database.arangodb.com/v1
+kind: ArangoDeployment
+metadata:
+  name: cluster
+spec:
+  image: arangodb:3.10
+  mode: Cluster
+  architecture:
+    - arm64
+```
+
+## Member Architecture change (Enterprise only)
+
+To migrate members from AMD64 to ARM64 you need to add `arm64` architecture to the existing deployment as a first item on the list, e.g.
+```yaml
+apiVersion: database.arangodb.com/v1
+kind: ArangoDeployment
+metadata:
+  name: cluster
+spec:
+  image: arangodb:3.10
+  mode: Cluster
+  architecture:
+    - arm64
+    - amd64
+```
+
+All new members since now will be created on ARM64 nodes
+All recreated members since now will be created on ARM64 nodes
+
+To change architecture of a specific member, you need to use following annotation:
 ```bash
-kubectl annotate pod arango-pod deployment.arangodb.com/arch=arm64
+kubectl annotate pod {MY_POD} deployment.arangodb.com/arch=arm64
 ```
 
 It will add to the member status `ArchitectureMismatch` condition, e.g.:
@@ -14,7 +60,7 @@ It will add to the member status `ArchitectureMismatch` condition, e.g.:
     type: ArchitectureMismatch
 ```
 
-To provide requested arch changes for the member we need rotate it, so additional step is required:
+To provide requested arch changes for the member, we need to rotate it, so an additional step is required:
 ```bash
-`kubectl annotate pod arango-pod deployment.arangodb.com/rotate=true`
+`kubectl annotate pod {MY_POD} deployment.arangodb.com/rotate=true`
 ```

docs/design/features/failover_leader_service.md

@@ -0,0 +1,23 @@
+# Failover Leader service
+
+## Overview
+
+This feature is designed to solve the problem with the Leader service in Active Failover mode.
+It attaches the `deployment.arangodb.com/leader=true` label to the Leader member of the cluster.
+If a member is a Follower, then this label is removed.
+Above labels are used by the cluster Services to route the traffic to the Leader member.
+
+In case of double Leader situation (which will be fixed in future versions of ArangoDB), 
+the operator will remove the `deployment.arangodb.com/leader=true` label from all members, 
+which will cause the cluster outage.
+
+## How to use
+
+This feature is disabled by default.
+To enable it use `--deployment.feature.failover-leadership ` arg, which needs be passed to the operator:
+
+```shell
+helm upgrade --install kube-arangodb \
+https://github.com/arangodb/kube-arangodb/releases/download/$VER/kube-arangodb-$VER.tgz \
+  --set "operator.args={--deployment.feature.force-rebuild-out-synced-shards}"
+```

docs/design/rebuild_out_synced_shards.md renamed to docs/design/features/rebuild_out_synced_shards.md

@@ -22,7 +22,7 @@ This feature is disabled by default.
 
 Here is the example `helm` command which enables this feature and sets shard-rebuild timeout to 10 minutes:
 ```shell
-export VER=1.2.27; helm upgrade --install kube-arangodb \
+helm upgrade --install kube-arangodb \
 https://github.com/arangodb/kube-arangodb/releases/download/$VER/kube-arangodb-$VER.tgz \
   --set "operator.args={--deployment.feature.force-rebuild-out-synced-shards,--timeout.shard-rebuild=10m}"
 ```