Este blog es parte de una serie de blogs de varias partes que muestra cómo ejecutar sus aplicaciones en Kubernetes. Se utilizará el Couchbaseuna base de datos documental distribuida NoSQL de código abierto, como contenedor Docker.
La primera parte (Couchbase en Kubernetes) se explica cómo iniciar el clúster Kubernetes utilizando Vagrant. La segunda parte (Kubernetes en Amazon) explicó cómo ejecutar esa configuración en Amazon Web Services.
Esta tercera parte lo demostrará:
- Cómo configurar e iniciar el clúster Kubernetes en Google Cloud
- Ejecutar el contenedor Docker en el clúster Kubernetes
- Exponer Pod en Kubernetes como Servicio
- Apagar el clúster
He aquí un breve resumen:
Entremos en detalles.
Introducción a Google Compute Engine proporcionan instrucciones detalladas sobre cómo configurar Kubernetes en Google Cloud.
Descargar y configurar Google Cloud SDK
Hay un poco de configuración necesaria si nunca has accedido a Google Cloud en su máquina. Esto fue un poco abrumador y deseo se puede simplificar.
- Crear una cuenta facturable en Nube de Google
- Instale SDK de Google Cloud
- Configurar credenciales: gcloud auth login
- Crea un nuevo proyecto de Google Cloud y nómbralo
couchbase-on-kubernetes - Fija el proyecto:
gcloud config set project couchbase-on-kubernetes - Establecer zona por defecto:
gcloud config set compute/zone us-central1-a - Crea una instancia:
gcloud compute instances create example-instance --machine-type n1-standard-1 --image debian-8 - SSH en la instancia:
gcloud compute ssh ejemplo-instancia - Elimina la instancia:
gcloud compute instances delete ejemplo-instancia
Configuración del clúster Kubernetes en Google Cloud
El clúster Kubernetes se puede crear en Google Cloud como:
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set KUBERNETES_PROVIDER=gce ./cluster/kube-up.sh |
Asegúrese de que KUBERNETES_PROVIDER se establece en gce o no establecerlo en absoluto. Por defecto, esto aprovisiona un clúster Kubernetes de 4 nodos con un maestro. Esto significa que se crean 5 máquinas virtuales.
Si ha descargado Kubernetes desde github.com/kubernetes/kubernetes/releasestodos los valores pueden modificarse en cluster/aws/config-default.sh.
Iniciar Kubernetes en Google Cloud muestra el siguiente registro. Google Cloud SDK se comportaba un poco raro, pero tomando los valores predeterminados parecen funcionar:
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./kubernetes/cluster/kube-up.sh ... Starting cluster using provider: gce ... calling verify-prereqs You have specified individual components to update. If you are trying to install new components, use: $ gcloud components install alpha Do you want to run install instead (y/N)? Your current Cloud SDK version is: 99.0.0 Installing components from version: 99.0.0 ┌──────────────────────────────────────────────┐ │ These components will be installed. │ ├───────────────────────┬────────────┬─────────┤ │ Name │ Version │ Size │ ├───────────────────────┼────────────┼─────────┤ │ gcloud Alpha Commands │ 2016.01.12 │ < 1 MiB │ └───────────────────────┴────────────┴─────────┘ For the latest full release notes, please visit: https://cloud.google.com/sdk/release_notes Do you want to continue (Y/n)? ╔════════════════════════════════════════════════════════════╗ ╠═ Creating update staging area ═╣ ╠════════════════════════════════════════════════════════════╣ ╠═ Installing: gcloud Alpha Commands ═╣ ╠════════════════════════════════════════════════════════════╣ ╠═ Creating backup and activating new installation ═╣ ╚════════════════════════════════════════════════════════════╝ Performing post processing steps...done. Update done! You have specified individual components to update. If you are trying to install new components, use: $ gcloud components install beta Do you want to run install instead (y/N)? Your current Cloud SDK version is: 99.0.0 Installing components from version: 99.0.0 ┌─────────────────────────────────────────────┐ │ These components will be installed. │ ├──────────────────────┬────────────┬─────────┤ │ Name │ Version │ Size │ ├──────────────────────┼────────────┼─────────┤ │ gcloud Beta Commands │ 2016.01.12 │ < 1 MiB │ └──────────────────────┴────────────┴─────────┘ For the latest full release notes, please visit: https://cloud.google.com/sdk/release_notes Do you want to continue (Y/n)? ╔════════════════════════════════════════════════════════════╗ ╠═ Creating update staging area ═╣ ╠════════════════════════════════════════════════════════════╣ ╠═ Installing: gcloud Beta Commands ═╣ ╠════════════════════════════════════════════════════════════╣ ╠═ Creating backup and activating new installation ═╣ ╚════════════════════════════════════════════════════════════╝ Performing post processing steps...done. Update done! All components are up to date. ... calling kube-up Your active configuration is: [default] Project: couchbase-on-kubernetes Zone: us-central1-b Creating gs://kubernetes-staging-9479406781 Creating gs://kubernetes-staging-9479406781/... +++ Staging server tars to Google Storage: gs://kubernetes-staging-9479406781/devel +++ kubernetes-server-linux-amd64.tar.gz uploaded (sha1 = 1ff42f7c31837851d919a66fc07f34b9dbdacf28) +++ kubernetes-salt.tar.gz uploaded (sha1 = f307380ad6af7dabcf881b132146fa775c18dca8) Looking for already existing resources Starting master and configuring firewalls Created [https://www.googleapis.com/compute/v1/projects/couchbase-on-kubernetes/zones/us-central1-b/disks/kubernetes-master-pd]. NAME ZONE SIZE_GB TYPE STATUS kubernetes-master-pd us-central1-b 20 pd-ssd READY Created [https://www.googleapis.com/compute/v1/projects/couchbase-on-kubernetes/regions/us-central1/addresses/kubernetes-master-ip]. Created [https://www.googleapis.com/compute/v1/projects/couchbase-on-kubernetes/global/firewalls/default-default-ssh]. Created [https://www.googleapis.com/compute/v1/projects/couchbase-on-kubernetes/global/firewalls/kubernetes-master-https]. NAME NETWORK SRC_RANGES RULES SRC_TAGS TARGET_TAGS default-default-ssh default 0.0.0.0/0 tcp:22 NAME NETWORK SRC_RANGES RULES SRC_TAGS TARGET_TAGS kubernetes-master-https default 0.0.0.0/0 tcp:443 kubernetes-master +++ Logging using Fluentd to gcp ./kubernetes/cluster/../cluster/../cluster/gce/util.sh: line 434: @: unbound variable ./kubernetes/cluster/../cluster/../cluster/gce/util.sh: line 434: @: unbound variable ./kubernetes/cluster/../cluster/../cluster/gce/util.sh: line 434: @: unbound variable ./kubernetes/cluster/../cluster/../cluster/gce/util.sh: line 434: @: unbound variable Created [https://www.googleapis.com/compute/v1/projects/couchbase-on-kubernetes/global/firewalls/default-default-internal]. NAME NETWORK SRC_RANGES RULES SRC_TAGS TARGET_TAGS default-default-internal default 10.0.0.0/8 tcp:1-65535,udp:1-65535,icmp Created [https://www.googleapis.com/compute/v1/projects/couchbase-on-kubernetes/global/firewalls/kubernetes-minion-all]. NAME NETWORK SRC_RANGES RULES SRC_TAGS TARGET_TAGS kubernetes-minion-all default 10.244.0.0/16 tcp,udp,icmp,esp,ah,sctp kubernetes-minion Created [https://www.googleapis.com/compute/v1/projects/couchbase-on-kubernetes/zones/us-central1-b/instances/kubernetes-master]. NAME ZONE MACHINE_TYPE PREEMPTIBLE INTERNAL_IP EXTERNAL_IP STATUS kubernetes-master us-central1-b n1-standard-1 10.128.0.2 104.197.213.249 RUNNING Creating minions. ./kubernetes/cluster/../cluster/../cluster/gce/util.sh: line 434: @: unbound variable ./kubernetes/cluster/../cluster/../cluster/gce/util.sh: line 434: @: unbound variable Attempt 1 to create kubernetes-minion-template WARNING: You have selected a disk size of under [200GB]. This may result in poor I/O performance. For more information, see: https://developers.google.com/compute/docs/disks/persistent-disks#pdperformance. Created [https://www.googleapis.com/compute/v1/projects/couchbase-on-kubernetes/global/instanceTemplates/kubernetes-minion-template]. NAME MACHINE_TYPE PREEMPTIBLE CREATION_TIMESTAMP kubernetes-minion-template n1-standard-1 2016-03-03T14:01:14.322-08:00 Created [https://www.googleapis.com/compute/v1/projects/couchbase-on-kubernetes/zones/us-central1-b/instanceGroupManagers/kubernetes-minion-group]. NAME ZONE BASE_INSTANCE_NAME SIZE TARGET_SIZE INSTANCE_TEMPLATE AUTOSCALED kubernetes-minion-group us-central1-b kubernetes-minion 4 kubernetes-minion-template Waiting for group to become stable, current operations: creating: 4 Waiting for group to become stable, current operations: creating: 4 Waiting for group to become stable, current operations: creating: 4 Waiting for group to become stable, current operations: creating: 4 Waiting for group to become stable, current operations: creating: 4 Waiting for group to become stable, current operations: creating: 4 Waiting for group to become stable, current operations: creating: 3 Group is stable MINION_NAMES=kubernetes-minion-1hmm kubernetes-minion-3x1d kubernetes-minion-h1ov kubernetes-minion-nshn Using master: kubernetes-master (external IP: 104.197.213.249) 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. cluster "couchbase-on-kubernetes_kubernetes" set. user "couchbase-on-kubernetes_kubernetes" set. context "couchbase-on-kubernetes_kubernetes" set. switched to context "couchbase-on-kubernetes_kubernetes". user "couchbase-on-kubernetes_kubernetes-basic-auth" set. Wrote config for couchbase-on-kubernetes_kubernetes to /Users/arungupta/.kube/config Kubernetes cluster is running. The master is running at: https://104.197.213.249 The user name and password to use is located in /Users/arungupta/.kube/config. ... calling validate-cluster Waiting for 4 ready nodes. 0 ready nodes, 0 registered. Retrying. Waiting for 4 ready nodes. 0 ready nodes, 2 registered. Retrying. Waiting for 4 ready nodes. 0 ready nodes, 3 registered. Retrying. Waiting for 4 ready nodes. 0 ready nodes, 4 registered. Retrying. Waiting for 4 ready nodes. 3 ready nodes, 4 registered. Retrying. Waiting for 4 ready nodes. 3 ready nodes, 4 registered. Retrying. Found 4 node(s). NAME LABELS STATUS AGE kubernetes-minion-1hmm kubernetes.io/hostname=kubernetes-minion-1hmm Ready 1m kubernetes-minion-3x1d kubernetes.io/hostname=kubernetes-minion-3x1d Ready 52s kubernetes-minion-h1ov kubernetes.io/hostname=kubernetes-minion-h1ov Ready 1m kubernetes-minion-nshn kubernetes.io/hostname=kubernetes-minion-nshn Ready 1m Validate output: NAME STATUS MESSAGE ERROR controller-manager Healthy ok nil scheduler Healthy ok nil etcd-0 Healthy {"health": "true"} nil etcd-1 Healthy {"health": "true"} nil Cluster validation succeeded Done, listing cluster services: Kubernetes master is running at https://104.197.213.249 GLBCDefaultBackend is running at https://104.197.213.249/api/v1/proxy/namespaces/kube-system/services/default-http-backend Heapster is running at https://104.197.213.249/api/v1/proxy/namespaces/kube-system/services/heapster KubeDNS is running at https://104.197.213.249/api/v1/proxy/namespaces/kube-system/services/kube-dns KubeUI is running at https://104.197.213.249/api/v1/proxy/namespaces/kube-system/services/kube-ui Grafana is running at https://104.197.213.249/api/v1/proxy/namespaces/kube-system/services/monitoring-grafana InfluxDB is running at https://104.197.213.249/api/v1/proxy/namespaces/kube-system/services/monitoring-influxdb |
Hay un par de variables no vinculadas y un mensaje de ADVERTENCIA, pero eso no parece romper el script. Google Cloud Console muestra: 
Se crean cinco instancias como se muestra - una para el nodo maestro y cuatro para los nodos trabajadores.
Ejecutar un contenedor Docker en un clúster Kubernetes en Google Cloud
Ahora que el clúster está en marcha, obtenga una lista de todos los nodos:
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./kubernetes/cluster/kubectl.sh get no NAME LABELS STATUS AGE kubernetes-minion-1hmm kubernetes.io/hostname=kubernetes-minion-1hmm Ready 47m kubernetes-minion-3x1d kubernetes.io/hostname=kubernetes-minion-3x1d Ready 46m kubernetes-minion-h1ov kubernetes.io/hostname=kubernetes-minion-h1ov Ready 47m kubernetes-minion-nshn kubernetes.io/hostname=kubernetes-minion-nshn Ready 47m |
Muestra cuatro nodos trabajadores. Crea un pod de Couchbase:
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./kubernetes/cluster/kubectl.sh run couchbase --image=arungupta/couchbase replicationcontroller "couchbase" created |
Observe que el nombre de la imagen puede especificarse en la CLI. Este comando crea un controlador de replicación con un único pod. El pod utiliza arungupta/couchbase Imagen Docker que proporciona un servidor Couchbase preconfigurado. Aquí se puede especificar cualquier imagen Docker.
Consigue todos los recursos de RC:
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./kubernetes/cluster/kubectl.sh get rc CONTROLLER CONTAINER(S) IMAGE(S) SELECTOR REPLICAS AGE couchbase couchbase arungupta/couchbase run=couchbase 1 48s |
Esto muestra el Controlador de Replicación que se crea para usted.
Consigue todos los Pods:
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./kubernetes/cluster/kubectl.sh get po NAME READY STATUS RESTARTS AGE couchbase-s8v9r 1/1 Running 0 1m |
La salida muestra el Pod que se crea como parte del Replication Controller.
Más información sobre el Pod:
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./kubernetes/cluster/kubectl.sh describe po couchbase-s8v9r Name: couchbase-s8v9r Namespace: default Image(s): arungupta/couchbase Node: kubernetes-minion-3x1d/10.128.0.3 Start Time: Thu, 03 Mar 2016 14:53:36 -0800 Labels: run=couchbase Status: Running Reason: Message: IP: 10.244.3.3 Replication Controllers: couchbase (1/1 replicas created) Containers: couchbase: Container ID: docker://601ee2e4c822814c3969a241e37c97bf4d0d209f952f24707ab308192d289098 Image: arungupta/couchbase Image ID: docker://298618e67e495c2535abd17b60241565e456a4c9ee96c923ecf844a9dbcccced QoS Tier: cpu: Burstable Requests: cpu: 100m State: Running Started: Thu, 03 Mar 2016 14:54:46 -0800 Ready: True Restart Count: 0 Environment Variables: Conditions: Type Status Ready True Volumes: default-token-frsd7: Type: Secret (a secret that should populate this volume) SecretName: default-token-frsd7 Events: FirstSeen LastSeen Count From SubobjectPath Reason Message ───────── ──────── ───── ──── ───────────── ────── ─────── 1m 1m 1 {kubelet kubernetes-minion-3x1d} implicitly required container POD Pulled Container image "gcr.io/google_containers/pause:0.8.0" already present on machine 1m 1m 1 {scheduler } Scheduled Successfully assigned couchbase-s8v9r to kubernetes-minion-3x1d 1m 1m 1 {kubelet kubernetes-minion-3x1d} implicitly required container POD Created Created with docker id c1de9da87f1e 1m 1m 1 {kubelet kubernetes-minion-3x1d} spec.containers{couchbase} Pulling Pulling image "arungupta/couchbase" 1m 1m 1 {kubelet kubernetes-minion-3x1d} implicitly required container POD Started Started with docker id c1de9da87f1e 29s 29s 1 {kubelet kubernetes-minion-3x1d} spec.containers{couchbase} Pulled Successfully pulled image "arungupta/couchbase" 29s 29s 1 {kubelet kubernetes-minion-3x1d} spec.containers{couchbase} Created Created with docker id 601ee2e4c822 29s 29s 1 {kubelet kubernetes-minion-3x1d} spec.containers{couchbase} Started Started with docker id 601ee2e4c822 |
Exponer Pod en Kubernetes como Servicio
Ahora que nuestro pod está funcionando, ¿cómo accedo al servidor Couchbase? Necesitas exponerlo fuera del cluster Kubernetes. El kubectl exponer toma un pod, servicio o controlador de replicación y lo expone como un Servicio Kubernetes.
Vamos a exponer el controlador de replicación creado anteriormente y exponerlo:
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./kubernetes/cluster/kubectl.sh expose rc couchbase --target-port=8091 --port=8091 --type=LoadBalancer service "couchbase" exposed |
Más información sobre el Servicio:
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./kubernetes/cluster/kubectl.sh describe svc couchbase Name: couchbase Namespace: default Labels: run=couchbase Selector: run=couchbase Type: LoadBalancer IP: 10.0.37.150 LoadBalancer Ingress: 104.197.118.35 Port: 8091/TCP NodePort: 30808/TCP Endpoints: 10.244.3.3:8091 Session Affinity: None Events: FirstSeen LastSeen Count From SubobjectPath Reason Message ───────── ──────── ───── ──── ───────────── ────── ─────── 2m 2m 1 {service-controller } CreatingLoadBalancer Creating load balancer 1m 1m 1 {service-controller } CreatedLoadBalancer Created load balancer |
En Entrada del Loadbalancer le proporciona la dirección IP del equilibrador de carga que ahora es de acceso público. Espera 3 minutos para que el equilibrador de carga se asiente. Accede a él usando el puerto 8091 y aparecerá la página de inicio de sesión de la Consola Web de Couchbase: 
Introduzca las credenciales como "Administrador" y "contraseña" para ver la Consola Web: 
Y así acabas de acceder a tu pod fuera del clúster Kubernetes.
Apagar el clúster Kubernetes
Por último, apague el clúster mediante cluster/kube-down.sh guión.
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./kubernetes/cluster/kube-down.sh Bringing down cluster using provider: gce You have specified individual components to update. If you are trying to install new components, use: $ gcloud components install alpha Do you want to run install instead (y/N)? All components are up to date. You have specified individual components to update. If you are trying to install new components, use: $ gcloud components install beta Do you want to run install instead (y/N)? All components are up to date. All components are up to date. Your active configuration is: [default] Project: couchbase-on-kubernetes Zone: us-central1-b Bringing down cluster Deleted [https://www.googleapis.com/compute/v1/projects/couchbase-on-kubernetes/zones/us-central1-b/instanceGroupManagers/kubernetes-minion-group]. Deleted [https://www.googleapis.com/compute/v1/projects/couchbase-on-kubernetes/global/instanceTemplates/kubernetes-minion-template]. Updated [https://www.googleapis.com/compute/v1/projects/couchbase-on-kubernetes/zones/us-central1-b/instances/kubernetes-master]. Deleted [https://www.googleapis.com/compute/v1/projects/couchbase-on-kubernetes/zones/us-central1-b/instances/kubernetes-master]. Deleted [https://www.googleapis.com/compute/v1/projects/couchbase-on-kubernetes/global/firewalls/kubernetes-master-https]. Deleted [https://www.googleapis.com/compute/v1/projects/couchbase-on-kubernetes/global/firewalls/kubernetes-minion-all]. Deleting routes kubernetes-ad3beb92-e18b-11e5-8e71-42010a800002 Deleted [https://www.googleapis.com/compute/v1/projects/couchbase-on-kubernetes/global/routes/kubernetes-ad3beb92-e18b-11e5-8e71-42010a800002]. Deleted [https://www.googleapis.com/compute/v1/projects/couchbase-on-kubernetes/regions/us-central1/addresses/kubernetes-master-ip]. property "clusters.couchbase-on-kubernetes_kubernetes" unset. property "users.couchbase-on-kubernetes_kubernetes" unset. property "users.couchbase-on-kubernetes_kubernetes-basic-auth" unset. property "contexts.couchbase-on-kubernetes_kubernetes" unset. property "current-context" unset. Cleared config for couchbase-on-kubernetes_kubernetes from /Users/arungupta/.kube/config Done |
¡Que aproveche!
