[tanka] Enforce manual selection of cockroachdb image (#1077)

* [tanka] Enforce manual selection of cockroachdb image

* Adjust README

build/README.md

@@ -284,6 +284,10 @@ a PR to that effect would be greatly appreciated.
         detection functionality (currently an R&D project tracking an initial
         draft of the upcoming ASTM standard).
 
+    1.  `VAR_CRDB_DOCKER_IMAGE_NAME`: Docker image of cockroach db pods. Until 
+        DSS v0.16, the recommended CockroachDB image name is `cockroachdb/cockroach:v21.2.7`.
+        From DSS v0.17, the recommended CockroachDB version is `cockroachdb/cockroach:v24.1.3`.
+
     1.  `VAR_CRDB_HOSTNAME_SUFFIX`: The domain name suffix shared by all of your
         CockroachDB nodes.  For instance, if your CRDB nodes were addressable at
         `0.db.example.com`, `1.db.example.com`, and `2.db.example.com`, then

build/deploy/examples/minimum/main.jsonnet

@@ -10,6 +10,7 @@ local metadata = metadataBase {
   single_cluster: false,
   enableScd: false, // <-- This boolean value is VAR_ENABLE_SCD
   cockroach+: {
+    image: 'VAR_CRDB_DOCKER_IMAGE_NAME',
     hostnameSuffix: 'VAR_CRDB_HOSTNAME_SUFFIX',
     locality: 'VAR_CRDB_LOCALITY',
     nodeIPs: ['VAR_CRDB_NODE_IP1', 'VAR_CRDB_NODE_IP2', 'VAR_CRDB_NODE_IP3'],

build/deploy/metadata_base.libsonnet

@@ -14,7 +14,7 @@
     shouldInit: false,  // Set this to true if you are starting a new cluster.
     grpc_port: 26257,
     http_port: 8080,
-    image: 'cockroachdb/cockroach:v21.2.7',
+    image: error 'must specify cockroach db image. Until DSS v0.16, the recommended CockroachDB image is `cockroachdb/cockroach:v21.2.7`. From DSS v0.17, the recommended CockroachDB image is cockroachdb/cockroach:v24.1.3. Example: cockroachdb/cockroach:v21.2.7',
     nodeIPs: error 'must supply the per-node ip addresses as an array', // For AWS, this array should contain the allocation id of the elastic ips.
     JoinExisting: [],
     storageClass: 'standard',