I have a K8s, currently running in single node (master+kubelet,172.16.100.81). I have an config server image which I will run it in pod. The image is talking to another pod named eureka server. Both two images are spring boot application. And eureka server's http address and port is defined by me. I need to transfer eureka server's http address and port to config pod so that it could talk to eureka server.
I start eureka server: ( pesudo code)
kubectl run eureka-server --image=eureka-server-image --port=8761
kubectl expose deployment eureka-server --type NodePort:31000
Then I use command "docker pull" to download config server image and run it as below:
kubectl run config-server --image=config-server-image --port=8888
kubectl expose deployment config-server --type NodePort:31001
With these steps, I did not find the way to transfer eureka-server http
server (master IP address 172.16.100.81:31000) to config server, are there
methods I could transer variable eureka-server=172.16.100.81:31000 to Pod config server? I know I shall use ingress in K8s networking, but currently I use NodePort.
Generally, you don't need nodePort when you want two pods to communicate with each other. A simpler clusterIP is enough.
Whenever you are exposing a deployment with a service, it will be internally discoverable from the DNS. Both of your exposed services can be accessed using:
http://config-server.default:31001 and http://eureka-server.default:31000. default is the namespace here.
172.16.100.81:31000 will make it accessible from outside the cluster.
Related
I used bitnami/kafka to deploy kafka on minikube. A describe of the pod kafka-0 looks says that server address is:
KAFKA_CFG_ADVERTISED_LISTENERS:INTERNAL://$(MY_POD_NAME).kafka-headless.default.svc.cluster.local:9093,CLIENT://$(MY_POD_NAME).kafka-headless.default.svc.cluster.local:9092
My kafka address is set like so in Spring config properties:
spring.kafka.bootstrap-servers=["kafka-0.kafka-headless.default.svc.cluster.local:9092"]
But when I try to send a message I get the following error:
Failed to construct kafka producer] with root cause:
org.apache.kafka.common.config.ConfigException:
Invalid url in bootstrap.servers: ["kafka-0.kafka-headless.default.svc.cluster.local:9092"]
Note that this works when I run kafka locally and set the bootstrap-servers address to localhost:9092
How do I fix this error? What is the correct kafka URL to use and where do I find it? thanks
Minikube network is different to the host network, you need a bridge.
The advertised listener is in the minikube realm, not findable from the host.
You could setup a service and an ingress in minikube pointing to your kafka, setup your hosts file to the ip address of the ingress and the hostname advertised.
spring.kafka.bootstrap-servers needs valid server hostnames along with port number as comma-separated
hostname-1:port,hostname-2:port
["kafka-0.kafka-headless.default.svc.cluster.local:9092"] is not looking like one!
I have been trying to deploy the Spring Boot application on kubernetes cluseter. But somehow I can not access the rest end point from outside the cluster.
Here are the steps which i performed
Setup the kubernetes cluster using kubespray following the guide - Kubernetes Cluster setup using Kubespray
Pushed the spring boot docker image to docker hub
Created kubernetes deployment
vagrant#node1:~/spring-boot$ kubectl create deployment demo --image=rahulwagh17/kubernetes:jhooq-k8s-springboot
deployment.apps/demo created
Exposed the deployment with external IP = 1.1.1.1
kubectl expose deployment demo --type=LoadBalancer --name=demo-service --external-ip=1.1.1.1 --port=8080
service/demo-service exposed
This is how my deployment is looking
vagrant#node1:~/spring-boot$ kubectl get deployment
NAME READY UP-TO-DATE AVAILABLE AGE
demo 1/1 1 1 24s
This is how my services are looking
vagrant#node1:~/spring-boot$ kubectl get service
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
demo-service LoadBalancer 10.233.31.159 1.1.1.1 8080:30099/TCP 13s
kubernetes ClusterIP 10.233.0.1 <none> 443/TCP 23h
I can curl the rest end point within the cluster without a problem
vagrant#node1:~/spring-boot$ curl 10.233.31.159:8080/hello
Hello - Jhooq-k8s
Problem I am facing - When i am trying to curl the rest point from outside the cluster, i can not do
$ curl http://1.1.1.1:30099/hello
curl: (7) Failed to connect to 1.1.1.1 port 30099: Operation timed out
I am little new to kubernetes, so any leads or suggestions are highly appreciated
Please try via below approach:
Via Node Port:- Which means NodeIP:NodePort and in this case, please get any node-ip and then run a command
curl http://$NODE_IP:30099/hello
and you should be able to access your service.
I have recently started exploring the microservice architecture using jhipster and was trying to install and run the jhipster-registry from docker hub. Docker shows that the registry is running, but I am unable to access it on port 8761.
Pulled the image with docker pull jhipster/jhipster-registry
Started the container with docker run --name jhipster-registry -d jhipster/jhipster-registry
Here's a snapshot of what docker container ls returns:
Am I missing something over here?
You are starting the JHipster Registry container, but you aren't exposing the port.
You can expose a port by passing the port flag -p 8761:8761 which will enable you to connect to it via localhost:8761 or 127.0.0.1:8761 in a browser.
You may need to configure some environment variables for the JHipster Registry to start correctly. These may depend on your generated app's options, such as authentication type. For convenience JHipster apps come with a docker-compose.yml file. You can start it with docker-compose -f src/main/docker/jhipster-registry.yml up, as documented.
I have a spring-config-sever project that I am trying to run via Docker. I can run it from the command line and my other services and browser successfully connect via:
http://localhost:8980/aservice/dev
However, if I run it via Docker, the call fails.
My config-server has a Dockerfile:
FROM openjdk:8-jdk-alpine
VOLUME /tmp
ARG JAR_FILE=build/libs/my-config-server-0.1.0.jar
ADD ${JAR_FILE} my-config-server-0.1.0.jar
EXPOSE 8980
ENTRYPOINT ["java","-Djava.security.egd=file:/dev/./urandom","-jar","/my-config-server-0.1.0.jar"]
I build via:
docker build -t my-config-server .
I am running it via:
docker run my-config-server -p 8980:8980
And then I confirm it is running via
docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
1cecafdf99fe my-config-server "java -Djava.securit…" 14 seconds ago Up 13 seconds 8980/tcp suspicious_brahmagupta
When I run it via Docker, the browse fails with a "ERR_CONNECTION_REFUSED" and my calling services fails with:
Could not locate PropertySource: I/O error on GET request for
"http://localhost:8980/aservice/dev": Connection refused (Connection
refused);
Adding full answer based on comments.
First, you have to specify -p before image name.
docker run -p 8980:8980 my-config-server.
Second, just configuring localhost with host port won't make your my-service container to talk to other container. locahost in container is within itself(not host). You will need to use appropriate docker networking model so both containers can talk to each other.
If you are on Linux, the default is Bridge so you can configure my-config-server container ip docker inspect {containerIp-of-config-server} as your config server endpoint.
Example if your my-config-server ip is 172.17.0.2 then endpoint is - http://172.17.0.2:8980/
spring:
cloud:
config:
uri: http://172.17.0.2:8980
Just follow the docker documentation for little bit more understanding on how networking works.
https://docs.docker.com/network/network-tutorial-standalone/
https://docs.docker.com/v17.09/engine/userguide/networking/
If you want to spin up both containers using docker-compose, then you can link both containers using service name. Just follow Networking in Compose.
I could imagine that the application only listens on localhost, ie 127.0.0.1.
You might want to try setting the property server.address to 0.0.0.0.
Then port 8980 should also be available externally.
I cannot access my Cassandra database, deployed on the same namespace in kubernetes.
My service has no cluster IP but an internal endpoint cassandra.hosting:9042 but whenever I try to connect from an internal spring application using
spring.data.cassandra.contact-points=cassandra.hosting
it fails with the error All host(s) tried for query failed
How did you configure your endpoint? Generally, all services and pods in a Kubernetes cluster are discoverable through a standard DNS notation. It looks like this:
<service-name>.<namespace>.svc.cluster.local # or
<pod-name>.<namespace>.svc.cluster.local # or
<pod-name>.<subdomain>.<namespace>.svc.cluster.local
If you are within the same namespace this would work too:
<service-name>
<pod-name>
<pod-name>.<subdomain>
I would also check either core-dns or kube-dns are running and ready:
kubectl -n kube-system get pods | grep dns