Verify: migrate from Google Memorystore to KiviDB

Compare key counts. On a cluster, run DBSIZE on each shard's primary and add them up, or let the script below do it.

redis-cli -h 10.0.0.3 -p 6379 -a "$REDIS_AUTH" --no-auth-warning INFO keyspace
redis-cli -h my-db.cloud.kividb.io -p 6380 --tls --cacert kividb-ca.pem --user kividbapp --pass "$KIVIDB_PASSWORD" INFO keyspace

Then spot-check random keys with the script in Migrate from Amazon ElastiCache: it compares type, value and TTL, and works with a cluster on either side.

SOURCE_CLUSTER=1 TARGET_CA=kividb-ca.pem python3 verify.py \
  "redis://:$(gcloud auth print-access-token)@10.0.0.5:6379" \
  "rediss://kividbapp:$KIVIDB_PASSWORD@my-db.cloud.kividb.io:6380" 2000