When a Spring Boot application is deployed on Openshift using the openjdk java 1.8 S2I docker image, the jolokia agent is deployed within the image and, when the docker container is starter, then it is instrumented by the java -javaagent parameter. The HTTPS service exposed by Jolokia allows to access using the HTTP protocol the information about the MBeans created within the JVM.
The Jolokia service can be customized using the following parameters defined within the DeploymentConfig resource as env variables :
- AB_JOLOKIA_USER = "jolokia"
- AB_JOLOKIA_PASSWORD = "admin123"
- AB_JOLOKIA_PASSWORD_RANDOM = "false"
Remark : The list of the paramters available is defined here
mvn clean package
java -javaagent:jar/jolokia-jvm-1.3.7-agent.jar=config=etc/jolokia.properties -jar target/spring-boot-jolokia-1.0.0-SNAPSHOT.jar
- Get the Jolokia Info
curl -v -u jolokia:admin123 http://localhost:8778/jolokia/
or
http --auth jolokia:admin123 http://localhost:8778/jolokia/version
...
{
"request": {
"type": "version"
},
"status": 200,
"timestamp": 1510659657,
"value": {
"agent": "1.3.7",
"config": {
"agentContext": "/jolokia",
"agentId": "192.168.1.80-52647-2503dbd3-jvm",
"agentType": "jvm",
"debug": "false",
"debugMaxEntries": "100",
"discoveryEnabled": "true",
"historyMaxEntries": "10",
"maxCollectionSize": "0",
"maxDepth": "15",
"maxObjects": "0"
},
"info": {
"product": "tomcat",
"vendor": "Apache",
"version": "8.5.23"
},
"protocol": "7.2"
}
}
- Get the Memory usage
http --auth jolokia:admin123 http://localhost:8778/jolokia/read/java.lang:type\=Memory/HeapMemoryUsage
HTTP/1.1 200 OK
...
{
"request": {
"attribute": "HeapMemoryUsage",
"mbean": "java.lang:type=Memory",
"type": "read"
},
"status": 200,
"timestamp": 1510660614,
"value": {
"committed": 378535936,
"init": 268435456,
"max": 3817865216,
"used": 132615736
}
}
oc new-project demo-jolokia
mvn clean package fabric8:deploy -Popenshift
- Get the jolokia route endpoint
JOLOKIA_URL=$(oc get route spring-boot-monitoring-jolokia -o jsonpath='https://{.spec.host}')
- Next issue a curl or httpie request
curl -k -u jolokia:admin123 $JOLOKIA_URL/jolokia/version
or
http --verify=no --auth jolokia:admin123 $JOLOKIA_URL/jolokia/version
- Create Service/Route on Openshift
oc delete route/spring-boot-http-jolokia
oc delete svc/spring-boot-http-jolokia
oc create -f src/fabric8/jolokia-svc.yaml
oc create -f src/fabric8/jolokia-route.yaml