Unable to debug java app through stack driver in google kubernetes cluster - kubernetes

I am trying to debug a java app on GKE cluster through stack driver.
I have created a GKE cluster with Allow full access to all Cloud APIs
I am following documentation: https://cloud.google.com/debugger/docs/setup/java
Here is my DockerFile:
FROM openjdk:8-jdk-alpine
VOLUME /tmp
ARG JAR_FILE
COPY ${JAR_FILE} alnt-watchlist-microservice.jar
ENTRYPOINT ["java","-Djava.security.egd=file:/dev/./urandom","-jar","/alnt-watchlist-microservice.jar"]
In documentation, it was written to add following lines in DockeFile:
RUN mkdir /opt/cdbg && \
wget -qO- https://storage.googleapis.com/cloud-debugger/compute-java/debian-wheezy/cdbg_java_agent_gce.tar.gz | \
tar xvz -C /opt/cdbg
RUN java -agentpath:/opt/cdbg/cdbg_java_agent.so
-Dcom.google.cdbg.module=tpm-watchlist
-Dcom.google.cdbg.version=v1
-jar /alnt-watchlist-microservice.jar
When I build DockerFile, It fails saying tar: invalid magic , tar: short read.
In stackdriver debug console, It always show 'No deployed application found'. Which application it will show? I have already 2 services deployed on my kubernetes cluster.
I have already executed
gcloud debug source gen-repo-info-file --output-directory="WEB-INF/classes/
in my project's directory.
It generated source-context.json. After its creation, I tried building docker image and its failing.

The debugger will be ready for use when you deploy your containerized app. You are getting No deployed application found error because your debugger agent is failing to download or unzip in dockerfile.
Please check this discussion to resolve the tar: invalid magic , tar: short read. error.

Unfortunately it looks like Alpine isn't regularly tested with Debugger. There's a sample setup here that might help you: https://github.com/GoogleCloudPlatform/cloud-debug-java#alpine-linux

I resolved the issue.
Firstly, you will have to use java image "gcr.io/google-appengine/openjdk" instead of Alpine one.
Secondly,
I was putting entry points without comma separated (Basically in wrong format)
ENTRYPOINT ["java","-agentpath:/opt/cdbg/cdbg_java_agent.so", "-Djava.security.egd=file:/dev/./urandom" ,"-Dcom.google.cdbg.module=watchlist"]

Related

Lens (K8s client) give error: exec: executable oci not found

I spent several hours looking at this Lens error for K8s. I installed Python, OCI-CLI for Windows 10 (I downloaded oci-cli offline installation, and run python install.py) and configured cluster access. Using CMD works ok:
kubectl command works fine, even get pods command works
But using Lens it gives me the error when connecting
Error getting Credentials: exec: executable oci not found
What am I missing?
I finally found the solution, it was to download kubectl.exe
https://storage.googleapis.com/kubernetes-release/release/v1.21.0/bin/windows/amd64/kubectl.exe
I put it in a folder on the disk, example c:\kubenetes
add that folder to the PATH environment variable.
Restart the PC. Without reboot it didn't work.

How can I change the config file of the mongo running on ECS

I changed the mongod.conf.orig of the mongo running on ECS, but when I restart, the changes are gone.
Here's the details:
I have a mongodb running on ECS, it always crashes due to out of memory.
I have found the reason, I set the ECS memory to 8G, but because the mongo is running in a container, it detected a higher memory.
when I run db.hostInfo()
I got the memSizeMB higher than 16G.
It caused that when I run db.serverStatus().wiredTiger.cache
I got a "maximum bytes configured" higher than 8G
so I need to reduce the wiredTigerCacheSizeGB in config file.
I used the command line copilot svc exec -c /bin/sh -n mongo to connect to it.
Then I found a file named mongod.conf.orig.
I ran apt-get install vim to install vi and edit this file mongod.conf.orig.
But after I restart the mongo task, all my changes are gone. include the vi I just installed.
Did anyone meet the same problem? Any information will be appreciated.
ECS containers has ephemeral storage. In your case, you could create an EFS and mount it in a container, then share the configuration.
If you use CloudFormation, look at mount points.

How to resolve DNS lookup error when trying to run example microservice application using minikube

Dear StackOverflow community!
I am trying to run the https://github.com/GoogleCloudPlatform/microservices-demo locally on minikube, so I am following their development guide: https://github.com/GoogleCloudPlatform/microservices-demo/blob/master/docs/development-guide.md
After I successfully set up minikube (using virtualbox driver, but I tried also hyperkit, however the results were the same) and execute skaffold run, after some time it will end up with following error:
Building [shippingservice]...
Sending build context to Docker daemon 127kB
Step 1/14 : FROM golang:1.15-alpine as builder
---> 6466dd056dc2
Step 2/14 : RUN apk add --no-cache ca-certificates git
---> Running in 0e6d2ab2a615
fetch https://dl-cdn.alpinelinux.org/alpine/v3.13/main/x86_64/APKINDEX.tar.gz
WARNING: Ignoring https://dl-cdn.alpinelinux.org/alpine/v3.13/main: DNS lookup error
fetch https://dl-cdn.alpinelinux.org/alpine/v3.13/community/x86_64/APKINDEX.tar.gz
WARNING: Ignoring https://dl-cdn.alpinelinux.org/alpine/v3.13/community: DNS lookup error
ERROR: unable to select packages:
git (no such package):
required by: world[git]
Building [recommendationservice]...
Building [cartservice]...
Building [emailservice]...
Building [productcatalogservice]...
Building [loadgenerator]...
Building [checkoutservice]...
Building [currencyservice]...
Building [frontend]...
Building [adservice]...
unable to stream build output: The command '/bin/sh -c apk add --no-cache ca-certificates git' returned a non-zero code: 1. Please fix the Dockerfile and try again..
The error message suggest that DNS does not work. I tried to add 8.8.8.8 to /etc/resolv.conf on a minikube VM, but it did not help. I've noticed that after I re-run skaffold run and it fails again, the content /etc/resolv.conf returns to its original state containing 10.0.2.3 as the only DNS entry. Reaching the outside internet and pinging 8.8.8.8 form within the minikube VM works.
Could you point me to a direction how can possible I fix the problem and learn on how the DNS inside minikube/kubernetes works? I've heard that problems with DNS inside Kubernetes cluster are frequent problems you run into.
Thanks for your answers!
Best regards,
Richard
Tried it with docker driver, i.e. minikube start --driver=docker, and it works. Thanks Brian!
Sounds like issue was resolved for OP but if one is using docker inside minikube then below suggestion worked for me.
Ref: https://github.com/kubernetes/minikube/issues/10830
minikube ssh
$>sudo vi /etc/docker/daemon.json
# Add "dns": ["8.8.8.8"]
# save and exit
$>sudo systemctl restart docker

docker-compose - issue restarting single service

I am using docker-compose for a development project. I have 6 services defined in my docker compose file. I have been using the below script to rebuild the images whenever I make a change.
#!/bin/bash
# file: rebuild.sh
docker-compose down
docker-compose build
docker-compose up
I am looking for a way to reduce the build time as building and restarting all the services seems unnecessary as I am usually only changing one module. I see in the docker-compose docs you can run commands for individual services by specifying the service name after e.g. docker-compose build myservice.
In another terminal window I tried docker-compose build myservice && docker-compose restart myservice while leaving the other ./rebuild.sh command open in the original terminal. In the ./rebuild.sh terminal window I see all the initialization messages being reprinted to the stdout so I know it is restarting that service but the code changes aren't there. What am I doing wrong? I just want to rebuild and restart a single service.
Try:
docker-compose up -d --force-recreate --build myservice
Note that:
-d is for Detached mode,
-force-recreate will recreate containers even is your code did not change,
-build is for build your images before starting containers.
At least the name of your service.
Take a look here.

How to run kafka rest proxy on windows

How to run kafka rest proxy on windows.
I downloaded confluent-2.0.1-2.11.7.tar.gz
in windows folder i cannot see kafka-rest-start.
Windows isn't currently a supported platform. However, it should work fine if you adapt the script. Even just running java io.confluent.kafkarest.KafkaRestMain with the appropriate classpath should work.
Here's the example of the command they are actually executing in the end of the bash script:
java -Xmx256M -server -XX:+UseG1GC -XX:MaxGCPauseMillis=20 -XX:InitiatingHeapOccupancyPercent=35 -XX:+DisableExplicitGC -Djava.awt.headless=true -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false -Dlog4j.configuration=file:C:/Dev/kafka/confluent-4.0.0/etc/kafka-rest/log4j.properties -cp .;C:/Dev/kafka/confluent-4.0.0/target/kafka-rest-*-development/share/java/kafka-rest/*;C:/Dev/kafka/confluent-4.0.0/share/java/confluent-common/*;C:/Dev/kafka/confluent-4.0.0/share/java/rest-utils/*;C:/Dev/kafka/confluent-4.0.0/share/java/kafka-rest/* io.confluent.kafkarest.KafkaRestMain C:/Dev/kafka/confluent-4.0.0/etc/kafka-rest/kafka-rest.properties
Make sure you change paths to yours if you want to try it out.
Perhaps, this answer will help anybody who is new to Kafka and stumble upon this situation, like me :).
I was looking for an answer to the very same question a week ago, came across the official suggestion to run jar files(in this path confluent-x.x.x\share\java\kafka-rest) in windows and was NOT successful in doing so.
Always ran into this error no main attribute found with or without specifying the proper classpath and io.confluent.kafkarest.KafkaRestMain.
I even tried running the shell scripts packaged for Linux distribution using [babun]: http://babun.github.io/, but that resulted in the error like Error: Could not find or load main class io.confluent.kafkarest.KafkaRestMain .
Eventually, docker image built with zookeeper, kafka, schema-registry, kafka-rest worked like a charm.
Here is the official page with info about the image name, further reference to it's doc: https://hub.docker.com/r/confluentinc/cp-kafka-rest/
Upon pulling this image, a new virtual machine gets created with four more images inside it(one for each service like zookeeper, Kafka, schem-registry and Kafka-rest). Running the images runs a separate Docker container.
This guide should get you started quickly:
http://docs.confluent.io/current/cp-docker-images/docs/quickstart.html
And finally, if you would like to expose the kafka REST proxy server running as a Docker container to outside network(like windows machine which is part of the separate network than these containers) just mention the Docker host IP(find it by hitting docker-machine ip <hostname>) in KAFKA_REST_LISTENERS and expose the port with -p option.
Like this:
docker run -d \
--net=host \
--name=kafka-rest \
-p 8082:8082 \
-e KAFKA_REST_ZOOKEEPER_CONNECT=localhost:32181 \
-e KAFKA_REST_LISTENERS=http://192.168.99.100:8082 \
-e KAFKA_REST_SCHEMA_REGISTRY_URL=http://localhost:8081 \
-e KAFKA_REST_HOST_NAME=localhost \
confluentinc/cp-kafka-rest:3.2.1
If everything is OK, you will be able to access REST proxy at this url http://<Docker_host_IP>:8082 from the windows machine.
I was able to run the command that #lexler mentioned above, but outside of cygwin. (directly with the windows command prompt.)