gle-cloud-firewall-rule>Create a Google Cloud firewall rule</h2><p>To allow the pods on each cluster to directly communicate, create the following rule:</p><pre><code class=language-bash data-expandlinks=true data-repo=istio>$ function join_by { local IFS=&#34;$1&#34;; shift; echo &#34;$*&#34;; }
$ ALL_CLUSTER_CIDRS=$(gcloud container clusters list --format=&#39;value(clusterIpv4Cidr)&#39; | sort | uniq)
$ ALL_CLUSTER_CIDRS=$(join_by , $(echo &#34;${ALL_CLUSTER_CIDRS}&#34;))
$ ALL_CLUSTER_NETTAGS=$(gcloud c