Running webapp container is not able to find the Main class

[arun-gupta]

When a Docker image is generated for webapp using FMP, the Docker context has the following directory structure:

maven/webapp.war

The packaged WAR file has:

WEB-INF/classes/org/aws/samples/compute/webapp/Main.class

The java command to run the app is:

java -XX:+UseParallelGC -XX:GCTimeRatio=4 -XX:AdaptiveSizePolicyWeight=90 -XX:MinHeapFreeRatio=20 -XX:MaxHeapFreeRatio=40 -XX:+ExitOnOutOfMemoryError -cp .:/maven/* org.aws.samples.compute.webapp.Main

Running the Docker container arungupta/webapp as:

docker container run -d arungupta/webapp

gives the following error:

Error: Could not find or load main class org.aws.samples.compute.webapp.Main

[ALRubinger]

FMP command run to reproduce, and from services?

[kenfinnigan]

Had emailed @arun-gupta privately, but will respond with my thoughts here.

The Java command seems odd, as I would expect it to be running the -swarm.jar instead of a Main of any kind. The MANIFEST in -swarm.jar then points to the WF Swarm bootstrap Main class for uber jars, which in turn then executes the WF Swarm Main class, or in this case the custom Main class provided by the webapp project.

[arun-gupta]

mvn -pl webapp package -Pdocker produces the Docker image.

And then you run the container as docker container run -d arungupta/webapp.

[arun-gupta]

Now getting:

services $ docker container run -p 8080:8080 -it arungupta/webapp
ERROR: Neither $JAVA_MAIN_CLASS nor $JAVA_APP_JAR is set and 52 found in /deployments (1 expected)

[rafabene]

I've executed the last codebase and it worked! I can't reproduce this issue

[kenfinnigan]

I'm also unable to replicate that error with the latest code

[yanaga]

I've added a comment on PR #8, but I'll replicate here.

It happened to me before, so let me ask: are you running minikube or minishift and docker for mac at the same time? Sometimes the docker image gets pushed to the wrong registry. This seems to be the old image built with the error.

[arun-gupta]

I had Kubernetes enabled using Docker for Mac. Also had a kops-based cluster running. Terminated both of them and now the container is being built and run correctly. Here is the build output:

[INFO] --- fabric8-maven-plugin:3.5.30:build (default) @ webapp ---
[WARNING] Error reading service account token from: [/var/run/secrets/kubernetes.io/serviceaccount/token]. Ignoring.
[WARNING] Error reading service account token from: [/var/run/secrets/kubernetes.io/serviceaccount/token]. Ignoring.
[WARNING] F8: Cannot access cluster for detecting mode: Unknown host kubernetes.default.svc
[INFO] F8: Building Docker image in Kubernetes mode
[WARNING] Error reading service account token from: [/var/run/secrets/kubernetes.io/serviceaccount/token]. Ignoring.
[WARNING] F8: Cannot access cluster for detecting mode: Unknown host kubernetes.default.svc
[WARNING] Error reading service account token from: [/var/run/secrets/kubernetes.io/serviceaccount/token]. Ignoring.
[WARNING] F8: Cannot access cluster for detecting mode: Unknown host kubernetes.default.svc
[WARNING] Error reading service account token from: [/var/run/secrets/kubernetes.io/serviceaccount/token]. Ignoring.
[INFO] F8: Running generator wildfly-swarm
[INFO] F8: wildfly-swarm: Using Docker image fabric8/java-jboss-openjdk8-jdk:1.2 as base / builder
[WARNING] Error reading service account token from: [/var/run/secrets/kubernetes.io/serviceaccount/token]. Ignoring.
[WARNING] F8: Cannot access cluster for detecting mode: Unknown host kubernetes.default.svc
[WARNING] Error reading service account token from: [/var/run/secrets/kubernetes.io/serviceaccount/token]. Ignoring.
[WARNING] F8: Cannot access cluster for detecting mode: Unknown host kubernetes.default.svc
[WARNING] Error reading service account token from: [/var/run/secrets/kubernetes.io/serviceaccount/token]. Ignoring.
[INFO] Copying files to /Users/argu/workspaces/aws-compute-options/services/webapp/target/docker/arungupta/webapp/build/maven
[INFO] Building tar: /Users/argu/workspaces/aws-compute-options/services/webapp/target/docker/arungupta/webapp/tmp/docker-build.tar
[INFO] F8: [arungupta/webapp:latest] "wildfly-swarm": Created docker-build.tar in 344 milliseconds
[INFO] F8: [arungupta/webapp:latest] "wildfly-swarm": Built image sha256:c0fad
[INFO] F8: [arungupta/webapp:latest] "wildfly-swarm": Tag with latest
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 12.669 s
[INFO] Finished at: 2018-02-15T14:09:41-08:00
[INFO] Final Memory: 51M/506M
[INFO] ------------------------------------------------------------------------

How can I get rid of WARNING from the build output?

[kenfinnigan]

Glad it's working.

Not sure on the warnings, I see those as well

[arun-gupta]

Warnings are not showing up if a k8s cluster is already running. Will close this issue and open another one if this becomes bothersome.