# Creating a NATS Super Cluster in Digital Ocean with Helm Let's create a super cluster using NATS Gateways. First let's create 3 different clusters in NYC, Amsterdam, and San Francisco: ```sh doctl kubernetes cluster create nats-k8s-nyc1 --count 3 --region nyc1 doctl kubernetes cluster create nats-k8s-sfo2 --count 3 --region sfo2 doctl kubernetes cluster create nats-k8s-ams3 --count 3 --region ams3 ``` Next, open up the firewall across the 3 regions to be able to access the client, leafnode and gateways ports: ```sh for firewall in `doctl compute firewall list | tail -n 3 | awk '{print $1}'`; do doctl compute firewall add-rules $firewall --inbound-rules protocol:tcp,ports:4222,address:0.0.0.0/0 doctl compute firewall add-rules $firewall --inbound-rules protocol:tcp,ports:7422,address:0.0.0.0/0 doctl compute firewall add-rules $firewall --inbound-rules protocol:tcp,ports:7522,address:0.0.0.0/0 done ``` For this setup, we will create a super cluster using the external IPs from the nodes of the 3 clusters. For a production type of setup, it is recommended to use a DNS entry and an A record for each one of the servers. ```sh for ctx in do-ams3-nats-k8s-ams3 do-nyc1-nats-k8s-nyc1 do-sfo2-nats-k8s-sfo2; do echo "name: $ctx" for externalIP in `kubectl get nodes -o jsonpath='{.items[*].status.addresses[?(@.type=="ExternalIP")].address}'`; do echo "- nats://$externalIP:7522"; done echo done ``` The Helm definition would look as follows for the 3 clusters: ```yaml # super-cluster.yaml nats: externalAccess: true logging: debug: false trace: false cluster: enabled: true gateway: enabled: true # NOTE: defined via --set gateway.name="$ctx" # name: $ctx gateways: - name: do-ams3-nats-k8s-ams3 urls: - nats://142.93.251.181:7522 - nats://161.35.12.245:7522 - nats://161.35.2.153:7522 - name: do-nyc1-nats-k8s-nyc1 urls: - nats://142.93.251.181:7522 - nats://161.35.12.245:7522 - nats://161.35.2.153:7522 - name: do-sfo2-nats-k8s-sfo2 urls: - nats://142.93.251.181:7522 - nats://161.35.12.245:7522 - nats://161.35.2.153:7522 natsbox: enabled: true ``` Let's deploy the super cluster with Helm using the name of cluster as the name of the gateway: ```sh for ctx in do-ams3-nats-k8s-ams3 do-nyc1-nats-k8s-nyc1 do-sfo2-nats-k8s-sfo2; do helm --kube-context $ctx install nats nats/nats -f super-cluster.yaml --set gateway.name=$ctx done ``` That's it! It should now be possible to send some messages across regions: ```sh # Start subscription in Amsterdam nats-box:~# kubectl --context do-ams3-nats-k8s-ams3 exec -it nats-box -- /bin/sh -l nats-box:~# nats-sub -s nats hello # Send messages from San Francisco region nats-box:~# kubectl --context do-sfo2-nats-k8s-sfo2 exec -it nats-box -- /bin/sh -l nats-box:~# nats-pub -s nats hello 'Hello World!' # From outside of k8s can use the external IPs $ nats-sub -s 142.93.251.181 hello $ nats-pub -s 161.35.2.153 hello 'Hello World!' ``` # Using leafnodes and NATS super clusters to communicate across regions You can also create a multi-region NATS topology by using leafnodes connecting to a NATS super cluster (which could also be a much simpler way!). ```sh doctl kubernetes cluster create nats-k8s-nyc1 --count 3 --region nyc1 doctl kubernetes cluster create nats-k8s-sfo2 --count 3 --region sfo2 doctl kubernetes cluster create nats-k8s-ams3 --count 3 --region ams3 ``` Next, open up the firewall across the 3 regions to be able to access the client, leafnode and gateways ports: ```sh for firewall in `doctl compute firewall list | tail -n 3 | awk '{print $1}'`; do doctl compute firewall add-rules $firewall --inbound-rules protocol:tcp,ports:4222,address:0.0.0.0/0 done ``` The Helm definition would look as follows for the 3 clusters: ```yaml # nats.yaml leafnodes: enabled: true remotes: - url: tls://connect.ngs.global:7422 credentials: secret: name: ngs-creds key: NGS.creds natsbox: enabled: true ``` Let's deploy the super cluster with Helm using the name of cluster as the name of the gateway: ```sh for ctx in do-ams3-nats-k8s-ams3 do-nyc1-nats-k8s-nyc1 do-sfo2-nats-k8s-sfo2; do kubectl --context $ctx create secret generic ngs-creds --from-file $HOME/.nkeys/creds/synadia/NGS/NGS.creds helm --kube-context $ctx install nats nats/nats -f nats.yaml done ``` It should now be possible to send some messages across regions: ```sh # Start subscription in Amsterdam nats-box:~# kubectl --context do-ams3-nats-k8s-ams3 exec -it nats-box -- /bin/sh -l nats-box:~# nats-sub -s nats hello # Send messages from San Francisco region nats-box:~# kubectl --context do-sfo2-nats-k8s-sfo2 exec -it nats-box -- /bin/sh -l nats-box:~# nats-pub -s nats hello 'Hello World!' ``` Or from outside of k8s can use the external IPs: ```console # Find the external ips from the nodes $ for ctx in do-ams3-nats-k8s-ams3 do-nyc1-nats-k8s-nyc1 do-sfo2-nats-k8s-sfo2; do kubectl --context $ctx get nodes -o wide done NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-RUNTIME nats-k8s-ams3-default-pool-3cifn Ready 38m v1.17.5 10.133.7.58 188.166.32.235 Debian GNU/Linux 9 (stretch) 4.19.0-0.bpo.6-amd64 docker://18.9.2 nats-k8s-ams3-default-pool-3ciq9 Ready 38m v1.17.5 10.133.19.19 188.166.40.159 Debian GNU/Linux 9 (stretch) 4.19.0-0.bpo.6-amd64 docker://18.9.2 nats-k8s-ams3-default-pool-3ciqz Ready 38m v1.17.5 10.133.31.211 188.166.43.34 Debian GNU/Linux 9 (stretch) 4.19.0-0.bpo.6-amd64 docker://18.9.2 NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-RUNTIME nats-k8s-nyc1-default-pool-3ciq4 Ready 37m v1.17.5 10.136.75.202 161.35.125.69 Debian GNU/Linux 9 (stretch) 4.19.0-0.bpo.6-amd64 docker://18.9.2 nats-k8s-nyc1-default-pool-3ciqh Ready 38m v1.17.5 10.136.90.125 161.35.125.70 Debian GNU/Linux 9 (stretch) 4.19.0-0.bpo.6-amd64 docker://18.9.2 nats-k8s-nyc1-default-pool-3ciqk Ready 37m v1.17.5 10.136.65.137 161.35.125.66 Debian GNU/Linux 9 (stretch) 4.19.0-0.bpo.6-amd64 docker://18.9.2 NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-RUNTIME nats-k8s-sfo2-default-pool-3ciq0 Ready 37m v1.17.5 10.138.20.132 206.189.79.122 Debian GNU/Linux 9 (stretch) 4.19.0-0.bpo.6-amd64 docker://18.9.2 nats-k8s-sfo2-default-pool-3ciqd Ready 37m v1.17.5 10.138.4.194 64.225.124.243 Debian GNU/Linux 9 (stretch) 4.19.0-0.bpo.6-amd64 docker://18.9.2 nats-k8s-sfo2-default-pool-3ciqv Ready 37m v1.17.5 10.138.148.237 206.189.79.131 Debian GNU/Linux 9 (stretch) 4.19.0-0.bpo.6-amd64 docker://18.9.2 ``` Send a message from Amsterdam t SFO via the super cluster connected with leafnodes: ``` $ nats-sub -s 188.166.32.235 hello # From Amsterdam $ nats-pub -s 206.189.79.131 hello world # To SFO ```