Connect clients to Kubernetes clusters
Introduction
This document describes the different options to connect to a Yugabyte cluster deployed within Kubernetes.
Prerequisites
You must have set up a Yugabyte cluster according to the Kubernetes deployment instructions..
Connecting from within the Kubernetes cluster
An application that is deployed within the Kubernetes cluster should use the Service DNS name yb-tservers.<namespace>.svc.cluster.local to discover server endpoints. This DNS entry has multiple A records, one for each tserver pod, so that clients can randomize queries across different endpoints.
$ kubectl --namespace yb-demo get svc/yb-tservers
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
yb-tservers ClusterIP None <none> 7100/TCP,9000/TCP,6379/TCP,9042/TCP,5433/TCP 56m
Here is an example of a client that uses the YSQL shell (ysqlsh) to connect.
$ kubectl run ysqlsh-client -it --rm --image yugabytedb/yugabyte-client --command -- ysqlsh -h yb-tservers.yb-demo.svc.cluster.local
yugabyte=# CREATE TABLE demo(id INT PRIMARY KEY);
CREATE TABLE
Here is an example of a client that uses the YCQL shell (ycqlsh) to connect.
$ kubectl run cqlsh-shell -it --rm --image yugabytedb/yugabyte-client --command -- cqlsh yb-tservers.yb-demo.svc.cluster.local 9042
ycqlsh> CREATE KEYSPACE demo;
ycqlsh> use demo;
ycqlsh:demo> CREATE TABLE t_demo(id INT PRIMARY KEY);
Note that although tables are internally sharded across multiple tserver pods, every tserver pod has the ability to process any query, irrespective of its actual tablet assignment.
Connecting externally
An application that is deployed outside the Kubernetes cluster should use the external LoadBalancer IP address to connect to the cluster. Connections to the load balancer IP address are randomly routed to one of the tserver pods behind the yb-tservers service.
$ kubectl get svc -n yb-demo
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
yb-master-ui LoadBalancer 10.101.142.48 98.138.219.231 7000:32168/TCP 43h
yb-masters ClusterIP None <none> 7100/TCP,7000/TCP 43h
yb-tserver-service LoadBalancer 10.99.76.181 98.138.219.232 6379:30141/TCP,9042:31059/TCP,5433:30577/TCP 43h
yb-tservers ClusterIP None <none> 7100/TCP,9000/TCP,6379/TCP,9042/TCP,5433/TCP 43h
Here is an example of a client that uses the YSQL shell (ysqlsh to connect.
$ docker run yugabytedb/yugabyte-client ysqlsh -h 98.138.219.232
yugabyte=# CREATE TABLE demo(id INT PRIMARY KEY);
CREATE TABLE
Here is an example of a client that uses the YCQL shell (ycqlsh) to connect.
$ docker run yugabytedb/yugabyte-client ycqlsh 98.138.219.232 9042
ycqlsh> CREATE KEYSPACE demo;
ycqlsh> use demo;
ycqlsh:demo> CREATE TABLE t_demo(id INT PRIMARY KEY);
Master UI dashboard
The master UI dashboard is available at the external IP address exposed by the yb-master-ui LoadBalancer service - in this case at http://98.138.219.231:7000/.
Another option that does not require an external LoadBalancer is to create a tunnel from the local host to the master web server port on the master pod using kubectl port-forward .
$ kubectl port-forward pod/yb-master-0 7000:7000 -n yb-demo
Forwarding from 127.0.0.1:7000 -> 7000
Forwarding from [::1]:7000 -> 7000
Connecting externally to a Minikube cluster
When the Kubernetes cluster is set up using Minikube , an external IP address is not available by default for the LoadBalancer endpoints. To enable the load balancer IP address, run the command minikube tunnel. For details, see LoadBalancer access .
$ minikube tunnel
Status:
machine: minikube
pid: 38193
route: 10.96.0.0/12 -> 192.168.99.100
minikube: Running
services: [yb-master-ui, yb-tserver-service]
errors:
minikube: no errors
router: no errors
loadbalancer emulator: no errors