7.3. Verifying Stream Control Transmission Protocol (SCTP) is enabled
You can verify that SCTP is working on a cluster by creating a pod with an application that listens for SCTP traffic, associating it with a service, and then connecting to the exposed service.
Prerequisites
-
Access to the Internet from the cluster to install the
nc
package. -
Install the OpenShift CLI (
oc
). -
Access to the cluster as a user with the
cluster-admin
role.
Procedure
Create a pod starts an SCTP listener:
Create a file named
sctp-server.yaml
that defines a pod with the following YAML:apiVersion: v1 kind: Pod metadata: name: sctpserver labels: app: sctpserver spec: containers: - name: sctpserver image: registry.access.redhat.com/ubi8/ubi command: ["/bin/sh", "-c"] args: ["dnf install -y nc && sleep inf"] ports: - containerPort: 30102 name: sctpserver protocol: SCTP
Create the pod by entering the following command:
$ oc create -f sctp-server.yaml
Create a service for the SCTP listener pod.
Create a file named
sctp-service.yaml
that defines a service with the following YAML:apiVersion: v1 kind: Service metadata: name: sctpservice labels: app: sctpserver spec: type: NodePort selector: app: sctpserver ports: - name: sctpserver protocol: SCTP port: 30102 targetPort: 30102
To create the service, enter the following command:
$ oc create -f sctp-service.yaml
Create a pod for the SCTP client.
Create a file named
sctp-client.yaml
with the following YAML:apiVersion: v1 kind: Pod metadata: name: sctpclient labels: app: sctpclient spec: containers: - name: sctpclient image: registry.access.redhat.com/ubi8/ubi command: ["/bin/sh", "-c"] args: ["dnf install -y nc && sleep inf"]
To create the
Pod
object, enter the following command:$ oc apply -f sctp-client.yaml
Run an SCTP listener on the server.
To connect to the server pod, enter the following command:
$ oc rsh sctpserver
To start the SCTP listener, enter the following command:
$ nc -l 30102 --sctp
Connect to the SCTP listener on the server.
- Open a new terminal window or tab in your terminal program.
Obtain the IP address of the
sctpservice
service. Enter the following command:$ oc get services sctpservice -o go-template='{{.spec.clusterIP}}{{"\n"}}'
To connect to the client pod, enter the following command:
$ oc rsh sctpclient
To start the SCTP client, enter the following command. Replace
<cluster_IP>
with the cluster IP address of thesctpservice
service.# nc <cluster_IP> 30102 --sctp