This documentation is for a release that is no longer maintained
See documentation for the latest supported version 3 or the latest supported version 4.15.4. Configuring ingress cluster traffic using a load balancer
OpenShift Container Platform provides methods for communicating from outside the cluster with services running in the cluster. This method uses a load balancer.
If you do not need a specific external IP address, you can configure a load balancer service to allow external access to an OpenShift Container Platform cluster.
A load balancer service allocates a unique IP. The load balancer has a single edge router IP, which can be a virtual IP (VIP), but is still a single machine for initial load balancing.
If a pool is configured, it is done at the infrastructure level, not by a cluster administrator.
The procedures in this section require prerequisites performed by the cluster administrator.
15.4.2. Prerequisites 复制链接链接已复制到粘贴板!
Before starting the following procedures, the administrator must:
- Set up the external port to the cluster networking environment so that requests can reach the cluster.
Make sure there is at least one user with cluster admin role. To add this role to a user, run the following command:
oc adm policy add-cluster-role-to-user cluster-admin username
$ oc adm policy add-cluster-role-to-user cluster-admin username
Copy to Clipboard Copied! Toggle word wrap Toggle overflow - Have an OpenShift Container Platform cluster with at least one master and at least one node and a system outside the cluster that has network access to the cluster. This procedure assumes that the external system is on the same subnet as the cluster. The additional networking required for external systems on a different subnet is out-of-scope for this topic.
15.4.3. Creating a project and service 复制链接链接已复制到粘贴板!
If the project and service that you want to expose do not exist, first create the project, then the service.
If the project and service already exist, skip to the procedure on exposing the service to create a route.
Prerequisites
-
Install the
oc
CLI and log in as a cluster administrator.
Procedure
Create a new project for your service:
oc new-project <project_name>
$ oc new-project <project_name>
Copy to Clipboard Copied! Toggle word wrap Toggle overflow For example:
oc new-project myproject
$ oc new-project myproject
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Use the
oc new-app
command to create a service. For example:oc new-app \ -e MYSQL_USER=admin \ -e MYSQL_PASSWORD=redhat \ -e MYSQL_DATABASE=mysqldb \ registry.redhat.io/rhscl/mysql-80-rhel7
$ oc new-app \ -e MYSQL_USER=admin \ -e MYSQL_PASSWORD=redhat \ -e MYSQL_DATABASE=mysqldb \ registry.redhat.io/rhscl/mysql-80-rhel7
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Run the following command to see that the new service is created:
oc get svc -n myproject
$ oc get svc -n myproject
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Example output
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE mysql-80-rhel7 ClusterIP 172.30.63.31 <none> 3306/TCP 4m55s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE mysql-80-rhel7 ClusterIP 172.30.63.31 <none> 3306/TCP 4m55s
Copy to Clipboard Copied! Toggle word wrap Toggle overflow By default, the new service does not have an external IP address.
15.4.4. Exposing the service by creating a route 复制链接链接已复制到粘贴板!
You can expose the service as a route by using the oc expose
command.
Procedure
To expose the service:
- Log in to OpenShift Container Platform.
Log in to the project where the service you want to expose is located:
oc project myproject
$ oc project myproject
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Run the following command to expose the route:
oc expose service <service_name>
$ oc expose service <service_name>
Copy to Clipboard Copied! Toggle word wrap Toggle overflow For example:
oc expose service mysql-80-rhel7
$ oc expose service mysql-80-rhel7
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Example output
route "mysql-80-rhel7" exposed
route "mysql-80-rhel7" exposed
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Use a tool, such as cURL, to make sure you can reach the service using the cluster IP address for the service:
curl <pod_ip>:<port>
$ curl <pod_ip>:<port>
Copy to Clipboard Copied! Toggle word wrap Toggle overflow For example:
curl 172.30.131.89:3306
$ curl 172.30.131.89:3306
Copy to Clipboard Copied! Toggle word wrap Toggle overflow The examples in this section uses a MySQL service, which requires a client application. If you get a string of characters with the
Got packets out of order
message, you are connected to the service.If you have a MySQL client, log in with the standard CLI command:
mysql -h 172.30.131.89 -u admin -p
$ mysql -h 172.30.131.89 -u admin -p
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Example output
Enter password: Welcome to the MariaDB monitor. Commands end with ; or \g. MySQL [(none)]>
Enter password: Welcome to the MariaDB monitor. Commands end with ; or \g. MySQL [(none)]>
Copy to Clipboard Copied! Toggle word wrap Toggle overflow
15.4.5. Creating a load balancer service 复制链接链接已复制到粘贴板!
Use the following procedure to create a load balancer service.
Prerequisites
- Make sure that the project and service you want to expose exist.
Procedure
To create a load balancer service:
- Log in to OpenShift Container Platform.
Load the project where the service you want to expose is located.
oc project project1
$ oc project project1
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Open a text file on the master node and paste the following text, editing the file as needed:
Sample load balancer configuration file
Copy to Clipboard Copied! Toggle word wrap Toggle overflow - Save and exit the file.
Run the following command to create the service:
oc create -f <file-name>
$ oc create -f <file-name>
Copy to Clipboard Copied! Toggle word wrap Toggle overflow For example:
oc create -f mysql-lb.yaml
$ oc create -f mysql-lb.yaml
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Execute the following command to view the new service:
oc get svc
$ oc get svc
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Example output
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE egress-2 LoadBalancer 172.30.22.226 ad42f5d8b303045-487804948.example.com 3306:30357/TCP 15m
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE egress-2 LoadBalancer 172.30.22.226 ad42f5d8b303045-487804948.example.com 3306:30357/TCP 15m
Copy to Clipboard Copied! Toggle word wrap Toggle overflow The service has an external IP address automatically assigned if there is a cloud provider enabled.
On the master, use a tool, such as cURL, to make sure you can reach the service using the public IP address:
curl <public-ip>:<port>
$ curl <public-ip>:<port>
Copy to Clipboard Copied! Toggle word wrap Toggle overflow For example:
curl 172.29.121.74:3306
$ curl 172.29.121.74:3306
Copy to Clipboard Copied! Toggle word wrap Toggle overflow The examples in this section use a MySQL service, which requires a client application. If you get a string of characters with the
Got packets out of order
message, you are connecting with the service:If you have a MySQL client, log in with the standard CLI command:
mysql -h 172.30.131.89 -u admin -p
$ mysql -h 172.30.131.89 -u admin -p
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Example output
Enter password: Welcome to the MariaDB monitor. Commands end with ; or \g. MySQL [(none)]>
Enter password: Welcome to the MariaDB monitor. Commands end with ; or \g. MySQL [(none)]>
Copy to Clipboard Copied! Toggle word wrap Toggle overflow