Kubernetes 1.4 was released earlier this week. Read the blog announcement and CHANGELOG.
There are quite a few new features in this release but the key ones that I’m excited about are:
- Install Kubernetes using
kubeadm
command. This is in addition to the usual mechanism of downloading from https://github.com/kubernetes/kubernetes/releases. The
kubeadm init
andkubeadm join
commands looks very similar todocker swarm init
anddocker swarm join
for Docker Swarm Mode. - Federated Replica Sets
- ScheduledJob allows to run batch jobs at regular intervals.
- Constraining pods to a node and affinity and anti-affinity of pods
- Priority scheduling of pods
- Nice looking Kubernetes Dashboard (more on this later)
This blog will show:
- Create a Kubernetes cluster using Amazon Web Services
- Create a Couchbase service
- Run a Spring Boot application that stores a JSON document in Couchbase
All the resource description files in this blog are at github.com/arun-gupta/kubernetes-java-sample/tree/master/maven.
Start Kubernetes Cluster
Download binary github.com/kubernetes/kubernetes/releases/download/v1.4.0/kubernetes.tar.gz and extract Include kubernetes/cluster
in PATH Start
a 2-node Kubernetes cluster:
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NUM_NODES=2 NODE_SIZE=m3.medium KUBERNETES_PROVIDER=aws kube-up.sh |
The log will be shown as:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 |
... Starting cluster in us-west-2a using provider aws ... calling verify-prereqs ... calling kube-up Starting cluster using os distro: jessie Uploading to Amazon S3 +++ Staging server tars to S3 Storage: kubernetes-staging-0eaf81fbc51209dd47c13b6d8b424149/devel upload: ../../../../../var/folders/81/ttv4n16x7p390cttrm_675y00000gn/T/kubernetes.XXXXXX.bCmvLbtK/s3/bootstrap-script to s3://kubernetes-staging-0eaf81fbc51209dd47c13b6d8b424149/devel/bootstrap-script Uploaded server tars: SERVER_BINARY_TAR_URL: https://s3.amazonaws.com/kubernetes-staging-0eaf81fbc51209dd47c13b6d8b424149/devel/kubernetes-server-linux-amd64.tar.gz SALT_TAR_URL: https://s3.amazonaws.com/kubernetes-staging-0eaf81fbc51209dd47c13b6d8b424149/devel/kubernetes-salt.tar.gz BOOTSTRAP_SCRIPT_URL: https://s3.amazonaws.com/kubernetes-staging-0eaf81fbc51209dd47c13b6d8b424149/devel/bootstrap-script INSTANCEPROFILE arn:aws:iam::598307997273:instance-profile/kubernetes-master 2016-07-29T15:13:35Z AIPAJF3XKLNKOXOTQOCT4 kubernetes-master / ROLES arn:aws:iam::598307997273:role/kubernetes-master 2016-07-29T15:13:33Z / AROAI3Q2KFBD5PCKRXCRM kubernetes-master ASSUMEROLEPOLICYDOCUMENT 2012-10-17 STATEMENT sts:AssumeRole Allow PRINCIPAL ec2.amazonaws.com INSTANCEPROFILE arn:aws:iam::598307997273:instance-profile/kubernetes-minion 2016-07-29T15:13:39Z AIPAIYSH5DJA4UPQIP4BE kubernetes-minion / ROLES arn:aws:iam::598307997273:role/kubernetes-minion 2016-07-29T15:13:37Z / AROAIQ57MPQYSHRPQCT2Q kubernetes-minion ASSUMEROLEPOLICYDOCUMENT 2012-10-17 STATEMENT sts:AssumeRole Allow PRINCIPAL ec2.amazonaws.com Using SSH key with (AWS) fingerprint: SHA256:dX/5wpWuUxYar2NFuGwiZuRiydiZCyx4DGoZ5/jL/j8 Creating vpc. Adding tag to vpc-6b5b4b0f: Name=kubernetes-vpc Adding tag to vpc-6b5b4b0f: KubernetesCluster=kubernetes Using VPC vpc-6b5b4b0f Adding tag to dopt-8fe770eb: Name=kubernetes-dhcp-option-set Adding tag to dopt-8fe770eb: KubernetesCluster=kubernetes Using DHCP option set dopt-8fe770eb Creating subnet. Adding tag to subnet-623a0206: KubernetesCluster=kubernetes Using subnet subnet-623a0206 Creating Internet Gateway. Using Internet Gateway igw-251eab41 Associating route table. Creating route table Adding tag to rtb-d43cedb3: KubernetesCluster=kubernetes Associating route table rtb-d43cedb3 to subnet subnet-623a0206 Adding route to route table rtb-d43cedb3 Using Route Table rtb-d43cedb3 Creating master security group. Creating security group kubernetes-master-kubernetes. Adding tag to sg-d20ca0ab: KubernetesCluster=kubernetes Creating minion security group. Creating security group kubernetes-minion-kubernetes. Adding tag to sg-cd0ca0b4: KubernetesCluster=kubernetes Using master security group: kubernetes-master-kubernetes sg-d20ca0ab Using minion security group: kubernetes-minion-kubernetes sg-cd0ca0b4 Creating master disk: size 20GB, type gp2 Adding tag to vol-99a30b11: Name=kubernetes-master-pd Adding tag to vol-99a30b11: KubernetesCluster=kubernetes Allocated Elastic IP for master: 52.40.9.27 Adding tag to vol-99a30b11: kubernetes.io/master-ip=52.40.9.27 Generating certs for alternate-names: IP:52.40.9.27,IP:172.20.0.9,IP:10.0.0.1,DNS:kubernetes,DNS:kubernetes.default,DNS:kubernetes.default.svc,DNS:kubernetes.default.svc.cluster.local,DNS:kubernetes-master Starting Master Adding tag to i-f95bdae1: Name=kubernetes-master Adding tag to i-f95bdae1: Role=kubernetes-master Adding tag to i-f95bdae1: KubernetesCluster=kubernetes Waiting for master to be ready Attempt 1 to check for master nodeWaiting for instance i-f95bdae1 to be running (currently pending) Sleeping for 3 seconds... Waiting for instance i-f95bdae1 to be running (currently pending) Sleeping for 3 seconds... [master running] Attaching IP 52.40.9.27 to instance i-f95bdae1 Attaching persistent data volume (vol-99a30b11) to master 2016-09-29T05:14:28.098Z /dev/sdb i-f95bdae1 attaching vol-99a30b11 cluster "aws_kubernetes" set. user "aws_kubernetes" set. context "aws_kubernetes" set. switched to context "aws_kubernetes". user "aws_kubernetes-basic-auth" set. Wrote config for aws_kubernetes to /Users/arungupta/.kube/config Creating minion configuration Creating autoscaling group 0 minions started; waiting 0 minions started; waiting 0 minions started; waiting 0 minions started; waiting 2 minions started; ready Waiting for cluster initialization. This will continually check to see if the API for kubernetes is reachable. This might loop forever if there was some uncaught error during start up. ..............................................................................................................................................................................................................................Kubernetes cluster created. Sanity checking cluster... Attempt 1 to check Docker on node @ 54.70.225.33 ...working Attempt 1 to check Docker on node @ 54.71.36.48 ...working Kubernetes cluster is running. The master is running at: https://52.40.9.27 The user name and password to use is located in /Users/arungupta/.kube/config. ... calling validate-cluster Waiting for 2 ready nodes. 0 ready nodes, 0 registered. Retrying. Waiting for 2 ready nodes. 0 ready nodes, 0 registered. Retrying. Waiting for 2 ready nodes. 0 ready nodes, 0 registered. Retrying. Waiting for 2 ready nodes. 0 ready nodes, 2 registered. Retrying. Waiting for 2 ready nodes. 0 ready nodes, 2 registered. Retrying. Found 2 node(s). NAME STATUS AGE ip-172-20-0-111.us-west-2.compute.internal Ready 39s ip-172-20-0-112.us-west-2.compute.internal Ready 42s Validate output: NAME STATUS MESSAGE ERROR scheduler Healthy ok controller-manager Healthy ok etcd-0 Healthy {"health": "true"} etcd-1 Healthy {"health": "true"} Cluster validation succeeded Done, listing cluster services: Kubernetes master is running at https://52.40.9.27 Elasticsearch is running at https://52.40.9.27/api/v1/proxy/namespaces/kube-system/services/elasticsearch-logging Heapster is running at https://52.40.9.27/api/v1/proxy/namespaces/kube-system/services/heapster Kibana is running at https://52.40.9.27/api/v1/proxy/namespaces/kube-system/services/kibana-logging KubeDNS is running at https://52.40.9.27/api/v1/proxy/namespaces/kube-system/services/kube-dns kubernetes-dashboard is running at https://52.40.9.27/api/v1/proxy/namespaces/kube-system/services/kubernetes-dashboard Grafana is running at https://52.40.9.27/api/v1/proxy/namespaces/kube-system/services/monitoring-grafana InfluxDB is running at https://52.40.9.27/api/v1/proxy/namespaces/kube-system/services/monitoring-influxdb To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'. |
This shows that the Kubernetes cluster has started successfully.
Deploy Couchbase Service
Create Couchbase service and replication controller:
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kubectl.sh create -f couchbase-service.yml service "couchbase-service" created replicationcontroller "couchbase-rc" created |
The configuration file is at github.com/arun-gupta/kubernetes-java-sample/blob/master/maven/couchbase-service.yml. This creates a Couchbase service and
the backing replication controller. Name of the service is couchbase-service
. This will be used later by the Spring Boot application to communicate with the database. Check the status of pods:
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kubectl.sh get -w pods NAME READY STATUS RESTARTS AGE couchbase-rc-gu9gl 0/1 ContainerCreating 0 6s NAME READY STATUS RESTARTS AGE couchbase-rc-gu9gl 1/1 Running 0 2m |
Note, how the pod status changes from ContainerCreating to Running. The image is downloaded and started in the meanwhile.
Run Spring Boot Application
Run the application:
1 2 |
kubectl.sh create -f bootiful-couchbase.yml pod "bootiful-couchbase" created |
The configuration file is at github.com/arun-gupta/kubernetes-java-sample/blob/master/maven/bootiful-couchbase.yml. In this service,
COUCHBASE_URI
environment variable value is set to couchbase-service
. This is the service name created earlier. Docker image used for this service is arungupta/bootiful-couchbase
and is created using
fabric8-maven-plugin as shown at github.com/arun-gupta/kubernetes-java-sample/blob/master/maven/webapp/pom.xml#L57-L68.
Specifically, the command for the Docker image is:
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java -Dspring.couchbase.bootstrap-hosts=$COUCHBASE_URI -jar /maven/${project.artifactId}.jar |
This ensures that COUCHBASE_URI
environment variable is overriding spring.couchbase.bootstrap-hosts
property as defined in application.properties of the Spring Boot application. Get the logs:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 |
kubectl.sh logs -f bootiful-couchbase . ____ _ __ _ _ /\ / ___'_ __ _ _(_)_ __ __ _ ( ( )___ | '_ | '_| | '_ / _` | \/ ___)| |_)| | | | | || (_| | ) ) ) ) ' |____| .__|_| |_|_| |___, | / / / / =========|_|==============|___/=/_/_/_/ :: Spring Boot :: (v1.4.0.RELEASE) 2016-09-29 05:37:29.227 INFO 5 --- [ main] org.example.webapp.Application : Starting Application v1.0-SNAPSHOT on bootiful-couchbase with PID 5 (/maven/bootiful-couchbase.jar started by root in /) 2016-09-29 05:37:29.259 INFO 5 --- [ main] org.example.webapp.Application : No active profile set, falling back to default profiles: default 2016-09-29 05:37:29.696 INFO 5 --- [ main] s.c.a.AnnotationConfigApplicationContext : Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@4ccabbaa: startup date [Thu Sep 29 05:37:29 UTC 2016]; root of context hierarchy 2016-09-29 05:37:34.375 INFO 5 --- [ main] c.c.client.core.env.CoreEnvironment : ioPoolSize is less than 3 (1), setting to: 3 2016-09-29 05:37:34.376 INFO 5 --- [ main] c.c.client.core.env.CoreEnvironment : computationPoolSize is less than 3 (1), setting to: 3 2016-09-29 05:37:35.026 INFO 5 --- [ main] com.couchbase.client.core.CouchbaseCore : CouchbaseEnvironment: {sslEnabled=false, sslKeystoreFile='null', sslKeystorePassword='null', queryEnabled=false, queryPort=8093, bootstrapHttpEnabled=true, bootstrapCarrierEnabled=true, bootstrapHttpDirectPort=8091, bootstrapHttpSslPort=18091, bootstrapCarrierDirectPort=11210, bootstrapCarrierSslPort=11207, ioPoolSize=3, computationPoolSize=3, responseBufferSize=16384, requestBufferSize=16384, kvServiceEndpoints=1, viewServiceEndpoints=1, queryServiceEndpoints=1, searchServiceEndpoints=1, ioPool=NioEventLoopGroup, coreScheduler=CoreScheduler, eventBus=DefaultEventBus, packageNameAndVersion=couchbase-java-client/2.2.8 (git: 2.2.8, core: 1.2.9), dcpEnabled=false, retryStrategy=BestEffort, maxRequestLifetime=75000, retryDelay=ExponentialDelay{growBy 1.0 MICROSECONDS, powers of 2; lower=100, upper=100000}, reconnectDelay=ExponentialDelay{growBy 1.0 MILLISECONDS, powers of 2; lower=32, upper=4096}, observeIntervalDelay=ExponentialDelay{growBy 1.0 MICROSECONDS, powers of 2; lower=10, upper=100000}, keepAliveInterval=30000, autoreleaseAfter=2000, bufferPoolingEnabled=true, tcpNodelayEnabled=true, mutationTokensEnabled=false, socketConnectTimeout=1000, dcpConnectionBufferSize=20971520, dcpConnectionBufferAckThreshold=0.2, dcpConnectionName=dcp/core-io, callbacksOnIoPool=false, queryTimeout=7500, viewTimeout=7500, kvTimeout=2500, connectTimeout=5000, disconnectTimeout=25000, dnsSrvEnabled=false} 2016-09-29 05:37:36.063 INFO 5 --- [ cb-io-1-1] com.couchbase.client.core.node.Node : Connected to Node couchbase-service 2016-09-29 05:37:36.256 INFO 5 --- [ cb-io-1-1] com.couchbase.client.core.node.Node : Disconnected from Node couchbase-service 2016-09-29 05:37:37.727 INFO 5 --- [ cb-io-1-2] com.couchbase.client.core.node.Node : Connected to Node couchbase-service 2016-09-29 05:37:38.316 INFO 5 --- [-computations-3] c.c.c.core.config.ConfigurationProvider : Opened bucket books 2016-09-29 05:37:40.655 INFO 5 --- [ main] o.s.j.e.a.AnnotationMBeanExporter : Registering beans for JMX exposure on startup Book{isbn=978-1-4919-1889-0, name=Minecraft Modding with Forge, cost=29.99} 2016-09-29 05:37:41.497 INFO 5 --- [ main] org.example.webapp.Application : Started Application in 14.64 seconds (JVM running for 16.631) 2016-09-29 05:37:41.514 INFO 5 --- [ Thread-5] s.c.a.AnnotationConfigApplicationContext : Closing org.springframework.context.annotation.AnnotationConfigApplicationContext@4ccabbaa: startup date [Thu Sep 29 05:37:29 UTC 2016]; root of context hierarchy 2016-09-29 05:37:41.528 INFO 5 --- [ Thread-5] o.s.j.e.a.AnnotationMBeanExporter : Unregistering JMX-exposed beans on shutdown 2016-09-29 05:37:41.577 INFO 5 --- [ cb-io-1-2] com.couchbase.client.core.node.Node : Disconnected from Node couchbase-service 2016-09-29 05:37:41.578 INFO 5 --- [ Thread-5] c.c.c.core.config.ConfigurationProvider : Closed bucket books |
The main output statement to look in this is
1 |
Book{isbn=978-1-4919-1889-0, name=Minecraft Modding with Forge, cost=29.99} |
This indicates that the JSON document is upserted (either inserted or updated) in the Couchbase database.
Kubernetes Dashboard
Kubernetes Dashboard is look more comprehensive and claimed to have 90% parity with the CLI. Use kubectl.sh config view
command to view the configuration information about the cluster. It looks like:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 |
apiVersion: v1 clusters: - cluster: certificate-authority-data: REDACTED server: https://52.40.9.27 name: aws_kubernetes contexts: - context: cluster: aws_kubernetes user: aws_kubernetes name: aws_kubernetes current-context: aws_kubernetes kind: Config preferences: {} users: - name: aws_kubernetes user: client-certificate-data: REDACTED client-key-data: REDACTED token: 3GuTCLvFnINHed9dWICICidlrSv8C0kg - name: aws_kubernetes-basic-auth user: password: 8pxC121Oj7kN0nCa username: admin |
The clusters.cluster.server
property value shows the location of Kubernetes master. The users
property show two users that can be used to access the dashboard. Second one uses basic authentication and so copy the
username
and password
property value. In our case, Dashboard UI is accessible at https://52.40.9.27/ui.
All the Kubernetes resources can be easily seen in this fancy dashboard.
Shutdown Kubernetes Cluster
Finally, shutdown the Kubernetes cluster:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 |
kube-down.sh Bringing down cluster using provider: aws Deleting instances in VPC: vpc-6b5b4b0f Deleting auto-scaling group: kubernetes-minion-group-us-west-2a Deleting auto-scaling launch configuration: kubernetes-minion-group-us-west-2a Deleting auto-scaling group: kubernetes-minion-group-us-west-2a Waiting for instances to be deleted Waiting for instance i-f95bdae1 to be terminated (currently shutting-down) Sleeping for 3 seconds... Waiting for instance i-f95bdae1 to be terminated (currently shutting-down) Sleeping for 3 seconds... Waiting for instance i-f95bdae1 to be terminated (currently shutting-down) Sleeping for 3 seconds... Waiting for instance i-f95bdae1 to be terminated (currently shutting-down) Sleeping for 3 seconds... Waiting for instance i-f95bdae1 to be terminated (currently shutting-down) Sleeping for 3 seconds... Waiting for instance i-f95bdae1 to be terminated (currently shutting-down) Sleeping for 3 seconds... Waiting for instance i-f95bdae1 to be terminated (currently shutting-down) Sleeping for 3 seconds... Waiting for instance i-f95bdae1 to be terminated (currently shutting-down) Sleeping for 3 seconds... Waiting for instance i-f95bdae1 to be terminated (currently shutting-down) Sleeping for 3 seconds... Waiting for instance i-f95bdae1 to be terminated (currently shutting-down) Sleeping for 3 seconds... Waiting for instance i-f95bdae1 to be terminated (currently shutting-down) Sleeping for 3 seconds... Waiting for instance i-f95bdae1 to be terminated (currently shutting-down) Sleeping for 3 seconds... Waiting for instance i-f95bdae1 to be terminated (currently shutting-down) Sleeping for 3 seconds... All instances deleted Releasing Elastic IP: 52.40.9.27 Deleting volume vol-99a30b11 Cleaning up resources in VPC: vpc-6b5b4b0f Cleaning up security group: sg-cd0ca0b4 Cleaning up security group: sg-d20ca0ab Deleting security group: sg-cd0ca0b4 Deleting security group: sg-d20ca0ab Deleting VPC: vpc-6b5b4b0f Done |
https://www.couchbase.com/products/cloud/kubernetes provide more details about running Couchbase using different orchestration frameworks. Further references:
- Couchbase Forums or StackOverflow
- Follow us at @couchbasedev or @couchbase
- Read more about Couchbase Server