Does anybody knows if API openshift-restclient-java can restart a POD - openshift

Question

I am trying programmatically to restart a POD in openshift? I can connect and query using this client API openshift-restclient-java
If so is there any sample code or link to one that can be provided?

Answer 1

I am currently playing around the first time with opensfhit-restclient-java and have achieved your task by doing as the following snippet illustrates.
What does the code do:
Scale the service instance to 0
Wait until the pod is really gone
Scale the service instance back to 1
Wait until the service instance is really up
Whatever needs to be done, when the service instance is up
Implementation:
private static boolean scaleDeployment(final IClient client,
final String dcName,
final String namespace,
final int scale) {
DeploymentConfig dc = client.get(ResourceKind.DEPLOYMENT_CONFIG, dcName, namespace);
boolean result = false;
if (dc != null) {
dc.setDesiredReplicaCount(scale);
client.update(dc);
result = true;
}
return result;
}
private static boolean waitForPodToDisappear(final IClient client,
final String namespace,
final Map<String, String> labels,
final int maxTries,
final int waitInMillis) {
int tries = 0;
List<Pod> pods = client.list(ResourceKind.POD, namespace, labels);
while (!pods.isEmpty() && tries < maxTries) {
pods = client.list(ResourceKind.POD, namespace, labels);
if (!pods.isEmpty()) {
tries += 1;
try {
Thread.sleep(waitInMillis);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
return pods.isEmpty();
}
private static boolean isPodReady(final Pod pod) {
final List<ModelNode> conditions = pod.getNode()
.get("status")
.get("conditions")
.asList();
return conditions.stream()
.filter(node -> (node.get("type").asString().contains("Ready")))
.filter(node -> node.get("status").asString().contains("True"))
.count() == 1;
}
private static boolean waitForPodToBecomeReady(final IClient client,
final String namespace,
final Map<String, String> labels,
final int maxTries,
final int waitInMillis) {
int tries = 0;
boolean result = false;
while (!result && tries < maxTries) {
final List<Pod> pods = client.list(ResourceKind.POD, namespace, labels);
if (pods.size() == 1) {
result = isPodReady(pods.get(0));
}
if (!result) {
tries += 1;
try {
Thread.sleep(waitInMillis);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
return result;
}
private static void main(String args[]) {
IClient client = new ClientBuilder().toCluster("https://127.0.0.1:8443")
.withConnectTimeout(2, TimeUnit.SECONDS)
.withUserName("developer")
.withPassword("developer")
.build();
boolean result = false;
// Stop service instance
scaleDeployment(client, "myservice-dc", "namespace", 0);
// Wait until service Pod is gone
result = waitForPodToDisappear(client, "namespace", new HashMap<String, String>() {{
put("name", "myservice-dc-label");
}}, 100, 1000);
if(result) {
// Start backup service instance
scaleDeployment(client, "myservice-dc", "namespace", 1);
result = waitForPodToBecomeReady(client, "namespace", new HashMap<String, String>() {{
put("name", "myservice-dc-label");
}}, 100, 1000);
if(result) {
// Do stuff, which requires the pod to be ready
}
}
}
As I already wrote, theses are my fist steps with the openshift-restclient-java.
You need the following dependency for oc 3.6+
<dependency>
<groupId>com.openshift</groupId>
<artifactId>openshift-restclient-java</artifactId>
<version>6.1.2.Final</version>
</dependency>

Answer 2

I used this method to restart the pod. I am posting this answer in case somebody have the same task.
def restartPod(podName: String, nameSpace: String): Boolean = {
val serviceList: Seq[IResource] = openshiftClient.list[IResource](ResourceKind.DEPLOYMENT_CONFIG, nameSpace).filter(service => service.getName.startsWith(podName)).toList
serviceList match {
case service :: _ => {
scaleTo(service, 0) match {
case None => println(s"Pod ${podName} successfully stopped.")
case Some(ex) => {
println(s"Error stopping pod ${podName} reason: ${ex.getMessage}")
}
}
scaleTo(service, 1) match {
case None => {
val message = s"Pod ${podName} successfully started."
println(message)
(true)
}
case Some(ex) => {
val message = s"Error starting pod ${podName} reason: ${ex.getMessage}"
logger.error(message)
(false)
}
}
}
case _ => {
val message = s"Pod ${podName} could not be restarted because it was not found with that name."
logger.error(message)
(false)
}
}
}
You would need the following library:
<dependency>
<groupId>com.openshift</groupId>
<artifactId>openshift-restclient-java</artifactId>
<version>1.0.1.6</version>
</dependency>