Cloud Composer 1 | Cloud Composer 2
Cette page explique comment utiliser les opérateurs Google Kubernetes Engine pour créer des clusters dans Google Kubernetes Engine et lancer des pods Kubernetes dans ces clusters.
Les opérateurs Google Kubernetes Engine exécutent des pods Kubernetes dans un cluster spécifié, qui peut être un cluster distinct et non lié à votre environnement.
En comparaison, KubernetesPodOperator exécute les pods Kubernetes dans le cluster de votre environnement.
Cette page présente un exemple de DAG qui crée un cluster Google Kubernetes Engine avec GKECreateClusterOperator, utilise GKEStartPodOperator avec les configurations suivantes, puis le supprime avec GKEDeleteClusterOperator par la suite :
Avant de commencer
Nous vous recommandons d'utiliser la dernière version de Cloud Composer. Cette version doit être au minimum compatible avec le règlement sur les abandons de versions et la compatibilité .
Configuration de l'opérateur GKE
Pour suivre cet exemple, placez l'intégralité du fichier gke_operator.py dans le dossier dags/ de votre environnement ou ajoutez le code pertinent à un DAG.
Créer un cluster
Le code présenté ici crée un cluster Google Kubernetes Engine doté de deux pools de nœuds, pool-0 et pool-1, chacun disposant d'un nœud. Si nécessaire, vous pouvez définir d'autres paramètres à partir de l'API Google Kubernetes Engine dans le fichier body.
Remarque :Nous vous recommandons d'utiliser des clusters régionaux dans Airflow 2. Les clusters zonaux sont plus exposés aux défaillances de zone. Par exemple, vous pouvez utiliser us-central1 comme zone pour votre cluster au lieu de us-central1-a. Avant la publication de la version 5.1.0 de apache-airflow-providers-google, il n'était pas possible de transmettre l'objet node_pools dans GKECreateClusterOperator. Si vous utilisez Airflow 2, assurez-vous que votre environnement utilise apache-airflow-providers-google version 5.1.0 ou ultérieure. Vous pouvez installer une version plus récente de ce package PyPI en spécifiant apache-airflow-providers-google et >=5.1.0 comme version requise.
Pour contourner ce problème pour les utilisateurs d'Airflow 1, nous utilisons BashOperator et gcloud pour créer ces pools de nœuds .
Lancer des charges de travail dans le cluster
Les sections suivantes décrivent chacune des configurations de GKEStartPodOperator de l'exemple. Pour en savoir plus sur chaque variable de configuration, consultez la documentation de référence Airflow pour les opérateurs GKE .
from airflow import models
from airflow.providers.google.cloud.operators.kubernetes_engine import (
GKECreateClusterOperator ,
GKEDeleteClusterOperator ,
GKEStartPodOperator ,
)
from airflow.utils.dates import days_ago
from kubernetes.client import models as k8s_models
with models . DAG (
"example_gcp_gke" ,
schedule_interval = None , # Override to match your needs
start_date = days_ago ( 1 ),
tags = [ "example" ],
) as dag :
# TODO(developer): update with your values
PROJECT_ID = "my-project-id"
# It is recommended to use regional clusters for increased reliability
# though passing a zone in the location parameter is also valid
CLUSTER_REGION = "us-west1"
CLUSTER_NAME = "example-cluster"
CLUSTER = {
"name" : CLUSTER_NAME ,
"node_pools" : [
{ "name" : "pool-0" , "initial_node_count" : 1 },
{ "name" : "pool-1" , "initial_node_count" : 1 },
],
}
create_cluster = GKECreateClusterOperator (
task_id = "create_cluster" ,
project_id = PROJECT_ID ,
location = CLUSTER_REGION ,
body = CLUSTER ,
)
kubernetes_min_pod = GKEStartPodOperator (
# The ID specified for the task.
task_id = "pod-ex-minimum" ,
# Name of task you want to run, used to generate Pod ID.
name = "pod-ex-minimum" ,
project_id = PROJECT_ID ,
location = CLUSTER_REGION ,
cluster_name = CLUSTER_NAME ,
# Entrypoint of the container, if not specified the Docker container's
# entrypoint is used. The cmds parameter is templated.
cmds = [ "echo" ],
# The namespace to run within Kubernetes, default namespace is
# `default`.
namespace = "default" ,
# Docker image specified. Defaults to hub.docker.com, but any fully
# qualified URLs will point to a custom repository. Supports private
# gcr.io images if the Composer Environment is under the same
# project-id as the gcr.io images and the service account that Composer
# uses has permission to access the Google Container Registry
# (the default service account has permission)
image = "gcr.io/gcp-runtimes/ubuntu_18_0_4" ,
)
kubenetes_template_ex = GKEStartPodOperator (
task_id = "ex-kube-templates" ,
name = "ex-kube-templates" ,
project_id = PROJECT_ID ,
location = CLUSTER_REGION ,
cluster_name = CLUSTER_NAME ,
namespace = "default" ,
image = "bash" ,
# All parameters below are able to be templated with jinja -- cmds,
# arguments, env_vars, and config_file. For more information visit:
# https://airflow.apache.org/docs/apache-airflow/stable/macros-ref.html
# Entrypoint of the container, if not specified the Docker container's
# entrypoint is used. The cmds parameter is templated.
cmds = [ "echo" ],
# DS in jinja is the execution date as YYYY-MM-DD, this docker image
# will echo the execution date. Arguments to the entrypoint. The docker
# image's CMD is used if this is not provided. The arguments parameter
# is templated.
arguments = [ "{{ ds }}" ],
# The var template variable allows you to access variables defined in
# Airflow UI. In this case we are getting the value of my_value and
# setting the environment variable `MY_VALUE`. The pod will fail if
# `my_value` is not set in the Airflow UI.
env_vars = { "MY_VALUE" : "{{ var.value.my_value }}" },
)
kubernetes_affinity_ex = GKEStartPodOperator (
task_id = "ex-pod-affinity" ,
project_id = PROJECT_ID ,
location = CLUSTER_REGION ,
cluster_name = CLUSTER_NAME ,
name = "ex-pod-affinity" ,
namespace = "default" ,
image = "perl" ,
cmds = [ "perl" ],
arguments = [ "-Mbignum=bpi" , "-wle" , "print bpi(2000)" ],
# affinity allows you to constrain which nodes your pod is eligible to
# be scheduled on, based on labels on the node. In this case, if the
# label 'cloud.google.com/gke-nodepool' with value
# 'nodepool-label-value' or 'nodepool-label-value2' is not found on any
# nodes, it will fail to schedule.
affinity = {
"nodeAffinity" : {
# requiredDuringSchedulingIgnoredDuringExecution means in order
# for a pod to be scheduled on a node, the node must have the
# specified labels. However, if labels on a node change at
# runtime such that the affinity rules on a pod are no longer
# met, the pod will still continue to run on the node.
"requiredDuringSchedulingIgnoredDuringExecution" : {
"nodeSelectorTerms" : [
{
"matchExpressions" : [
{
# When nodepools are created in Google Kubernetes
# Engine, the nodes inside of that nodepool are
# automatically assigned the label
# 'cloud.google.com/gke-nodepool' with the value of
# the nodepool's name.
"key" : "cloud.google.com/gke-nodepool" ,
"operator" : "In" ,
# The label key's value that pods can be scheduled
# on.
"values" : [
"pool-1" ,
],
}
]
}
]
}
}
},
)
kubernetes_full_pod = GKEStartPodOperator (
task_id = "ex-all-configs" ,
name = "full" ,
project_id = PROJECT_ID ,
location = CLUSTER_REGION ,
cluster_name = CLUSTER_NAME ,
namespace = "default" ,
image = "perl:5.34.0" ,
# Entrypoint of the container, if not specified the Docker container's
# entrypoint is used. The cmds parameter is templated.
cmds = [ "perl" ],
# Arguments to the entrypoint. The docker image's CMD is used if this
# is not provided. The arguments parameter is templated.
arguments = [ "-Mbignum=bpi" , "-wle" , "print bpi(2000)" ],
# The secrets to pass to Pod, the Pod will fail to create if the
# secrets you specify in a Secret object do not exist in Kubernetes.
secrets = [],
# Labels to apply to the Pod.
labels = { "pod-label" : "label-name" },
# Timeout to start up the Pod, default is 120.
startup_timeout_seconds = 120 ,
# The environment variables to be initialized in the container
# env_vars are templated.
env_vars = { "EXAMPLE_VAR" : "/example/value" },
# If true, logs stdout output of container. Defaults to True.
get_logs = True ,
# Determines when to pull a fresh image, if 'IfNotPresent' will cause
# the Kubelet to skip pulling an image if it already exists. If you
# want to always pull a new image, set it to 'Always'.
image_pull_policy = "Always" ,
# Annotations are non-identifying metadata you can attach to the Pod.
# Can be a large range of data, and can include characters that are not
# permitted by labels.
annotations = { "key1" : "value1" },
# Optional resource specifications for Pod, this will allow you to
# set both cpu and memory limits and requirements.
# Prior to Airflow 2.3 and the cncf providers package 5.0.0
# resources were passed as a dictionary. This change was made in
# https://github.com/apache/airflow/pull/27197
# Additionally, "memory" and "cpu" were previously named
# "limit_memory" and "limit_cpu"
# resources={'limit_memory': "250M", 'limit_cpu': "100m"},
container_resources = k8s_models . V1ResourceRequirements (
limits = { "memory" : "250M" , "cpu" : "100m" },
),
# If true, the content of /airflow/xcom/return.json from container will
# also be pushed to an XCom when the container ends.
do_xcom_push = False ,
# List of Volume objects to pass to the Pod.
volumes = [],
# List of VolumeMount objects to pass to the Pod.
volume_mounts = [],
# Affinity determines which nodes the Pod can run on based on the
# config. For more information see:
# https://kubernetes.io/docs/concepts/configuration/assign-pod-node/
affinity = {},
)
delete_cluster = GKEDeleteClusterOperator (
task_id = "delete_cluster" ,
name = CLUSTER_NAME ,
project_id = PROJECT_ID ,
location = CLUSTER_REGION ,
)
create_cluster >> kubernetes_min_pod >> delete_cluster
create_cluster >> kubernetes_full_pod >> delete_cluster
create_cluster >> kubernetes_affinity_ex >> delete_cluster
create_cluster >> kubenetes_template_ex >> delete_cluster
from airflow import models
from airflow.operators.bash_operator import BashOperator
from airflow.providers.google.cloud.operators.kubernetes_engine import (
GKECreateClusterOperator ,
GKEDeleteClusterOperator ,
GKEStartPodOperator ,
)
from airflow.utils.dates import days_ago
with models . DAG (
"example_gcp_gke" ,
schedule_interval = None , # Override to match your needs
start_date = days_ago ( 1 ),
tags = [ "example" ],
) as dag :
# TODO(developer): update with your values
PROJECT_ID = "my-project-id"
CLUSTER_ZONE = "us-west1-a"
CLUSTER_NAME = "example-cluster"
CLUSTER = { "name" : CLUSTER_NAME , "initial_node_count" : 1 }
create_cluster = GKECreateClusterOperator (
task_id = "create_cluster" ,
project_id = PROJECT_ID ,
location = CLUSTER_ZONE ,
body = CLUSTER ,
)
# Using the BashOperator to create node pools is a workaround
# In Airflow 2, because of https://github.com/apache/airflow/pull/17820
# Node pool creation can be done using the GKECreateClusterOperator
create_node_pools = BashOperator (
task_id = "create_node_pools" ,
bash_command = f "gcloud container node-pools create pool-0 \
--cluster { CLUSTER_NAME } \
--num-nodes 1 \
--zone { CLUSTER_ZONE } \
&& gcloud container node-pools create pool-1 \
--cluster { CLUSTER_NAME } \
--num-nodes 1 \
--zone { CLUSTER_ZONE } " ,
)
kubernetes_min_pod = GKEStartPodOperator (
# The ID specified for the task.
task_id = "pod-ex-minimum" ,
# Name of task you want to run, used to generate Pod ID.
name = "pod-ex-minimum" ,
project_id = PROJECT_ID ,
location = CLUSTER_ZONE ,
cluster_name = CLUSTER_NAME ,
# Entrypoint of the container, if not specified the Docker container's
# entrypoint is used. The cmds parameter is templated.
cmds = [ "echo" ],
# The namespace to run within Kubernetes, default namespace is
# `default`.
namespace = "default" ,
# Docker image specified. Defaults to hub.docker.com, but any fully
# qualified URLs will point to a custom repository. Supports private
# gcr.io images if the Composer Environment is under the same
# project-id as the gcr.io images and the service account that Composer
# uses has permission to access the Google Container Registry
# (the default service account has permission)
image = "gcr.io/gcp-runtimes/ubuntu_18_0_4" ,
)
kubenetes_template_ex = GKEStartPodOperator (
task_id = "ex-kube-templates" ,
name = "ex-kube-templates" ,
project_id = PROJECT_ID ,
location = CLUSTER_ZONE ,
cluster_name = CLUSTER_NAME ,
namespace = "default" ,
image = "bash" ,
# All parameters below are able to be templated with jinja -- cmds,
# arguments, env_vars, and config_file. For more information visit:
# https://airflow.apache.org/docs/apache-airflow/stable/macros-ref.html
# Entrypoint of the container, if not specified the Docker container's
# entrypoint is used. The cmds parameter is templated.
cmds = [ "echo" ],
# DS in jinja is the execution date as YYYY-MM-DD, this docker image
# will echo the execution date. Arguments to the entrypoint. The docker
# image's CMD is used if this is not provided. The arguments parameter
# is templated.
arguments = [ "{{ ds }}" ],
# The var template variable allows you to access variables defined in
# Airflow UI. In this case we are getting the value of my_value and
# setting the environment variable `MY_VALUE`. The pod will fail if
# `my_value` is not set in the Airflow UI.
env_vars = { "MY_VALUE" : "{{ var.value.my_value }}" },
)
kubernetes_affinity_ex = GKEStartPodOperator (
task_id = "ex-pod-affinity" ,
project_id = PROJECT_ID ,
location = CLUSTER_ZONE ,
cluster_name = CLUSTER_NAME ,
name = "ex-pod-affinity" ,
namespace = "default" ,
image = "perl" ,
cmds = [ "perl" ],
arguments = [ "-Mbignum=bpi" , "-wle" , "print bpi(2000)" ],
# affinity allows you to constrain which nodes your pod is eligible to
# be scheduled on, based on labels on the node. In this case, if the
# label 'cloud.google.com/gke-nodepool' with value
# 'nodepool-label-value' or 'nodepool-label-value2' is not found on any
# nodes, it will fail to schedule.
affinity = {
"nodeAffinity" : {
# requiredDuringSchedulingIgnoredDuringExecution means in order
# for a pod to be scheduled on a node, the node must have the
# specified labels. However, if labels on a node change at
# runtime such that the affinity rules on a pod are no longer
# met, the pod will still continue to run on the node.
"requiredDuringSchedulingIgnoredDuringExecution" : {
"nodeSelectorTerms" : [
{
"matchExpressions" : [
{
# When nodepools are created in Google Kubernetes
# Engine, the nodes inside of that nodepool are
# automatically assigned the label
# 'cloud.google.com/gke-nodepool' with the value of
# the nodepool's name.
"key" : "cloud.google.com/gke-nodepool" ,
"operator" : "In" ,
# The label key's value that pods can be scheduled
# on.
"values" : [
"pool-1" ,
],
}
]
}
]
}
}
},
)
kubernetes_full_pod = GKEStartPodOperator (
task_id = "ex-all-configs" ,
name = "full" ,
project_id = PROJECT_ID ,
location = CLUSTER_ZONE ,
cluster_name = CLUSTER_NAME ,
namespace = "default" ,
image = "perl" ,
# Entrypoint of the container, if not specified the Docker container's
# entrypoint is used. The cmds parameter is templated.
cmds = [ "perl" ],
# Arguments to the entrypoint. The docker image's CMD is used if this
# is not provided. The arguments parameter is templated.
arguments = [ "-Mbignum=bpi" , "-wle" , "print bpi(2000)" ],
# The secrets to pass to Pod, the Pod will fail to create if the
# secrets you specify in a Secret object do not exist in Kubernetes.
secrets = [],
# Labels to apply to the Pod.
labels = { "pod-label" : "label-name" },
# Timeout to start up the Pod, default is 120.
startup_timeout_seconds = 120 ,
# The environment variables to be initialized in the container
# env_vars are templated.
env_vars = { "EXAMPLE_VAR" : "/example/value" },
# If true, logs stdout output of container. Defaults to True.
get_logs = True ,
# Determines when to pull a fresh image, if 'IfNotPresent' will cause
# the Kubelet to skip pulling an image if it already exists. If you
# want to always pull a new image, set it to 'Always'.
image_pull_policy = "Always" ,
# Annotations are non-identifying metadata you can attach to the Pod.
# Can be a large range of data, and can include characters that are not
# permitted by labels.
annotations = { "key1" : "value1" },
# Resource specifications for Pod, this will allow you to set both cpu
# and memory limits and requirements.
# Prior to Airflow 1.10.4, resource specifications were
# passed as a Pod Resources Class object,
# If using this example on a version of Airflow prior to 1.10.4,
# import the "pod" package from airflow.contrib.kubernetes and use
# resources = pod.Resources() instead passing a dict
# For more info see:
# https://github.com/apache/airflow/pull/4551
resources = { "limit_memory" : "250M" , "limit_cpu" : "100m" },
# If true, the content of /airflow/xcom/return.json from container will
# also be pushed to an XCom when the container ends.
do_xcom_push = False ,
# List of Volume objects to pass to the Pod.
volumes = [],
# List of VolumeMount objects to pass to the Pod.
volume_mounts = [],
# Affinity determines which nodes the Pod can run on based on the
# config. For more information see:
# https://kubernetes.io/docs/concepts/configuration/assign-pod-node/
affinity = {},
)
delete_cluster = GKEDeleteClusterOperator (
task_id = "delete_cluster" ,
name = CLUSTER_NAME ,
project_id = PROJECT_ID ,
location = CLUSTER_ZONE ,
)
create_cluster >> create_node_pools >> kubernetes_min_pod >> delete_cluster
create_cluster >> create_node_pools >> kubernetes_full_pod >> delete_cluster
create_cluster >> create_node_pools >> kubernetes_affinity_ex >> delete_cluster
create_cluster >> create_node_pools >> kubenetes_template_ex >> delete_cluster
Configuration minimale
Pour lancer un pod dans votre cluster GKE avec la commande GKEStartPodOperator, seules les options project_id, location, cluster_name, name, namespace, image et task_id doivent être définies.
Lorsque vous placez l'extrait de code suivant dans un DAG, la tâche pod-ex-minimum réussit tant que les paramètres répertoriés précédemment sont définis et valides.
Configuration du modèle
Airflow est compatible avec la modélisation Jinja .
Vous devez déclarer les variables requises (task_id, name, namespace, image) avec l'opérateur. Comme le montre l'exemple suivant, vous pouvez modéliser tous les autres paramètres avec Jinja, y compris cmds, arguments et env_vars.
Sans modification du DAG ou de votre environnement, la tâche ex-kube-templates échoue. Définissez une variable Airflow appelée my_value pour que ce DAG aboutisse.
Pour définir my_value avec gcloud ou l'interface utilisateur d'Airflow, procédez comme suit :
Pour Airflow 2, saisissez la commande suivante :
gcloud composer environments run ENVIRONMENT \
--location LOCATION \
variables set -- \
my_value example_value
Pour Airflow 1, saisissez la commande suivante :
gcloud composer environments run ENVIRONMENT \
--location LOCATION \
variables -- \
--set my_value example_value
Remplacez :
ENVIRONMENT par le nom de l'environnement.LOCATION par la région dans laquelle se trouve l'environnement. Dans l'interface utilisateur d'Airflow 2:
Dans la barre d'outils, sélectionnez Admin > Variables (Administration > Variables).
Sur la page List Variable (Variable de liste), cliquez sur Add a new record (Ajouter un enregistrement).
Sur la page Add Variable (Ajouter une variable), saisissez les informations suivantes :
Key (Clé) : my_value
Val (Valeur) : example_value
Cliquez sur Enregistrer .
Dans l'interface utilisateur d'Airflow 1:
Dans la barre d'outils, sélectionnez Admin > Variables (Administration > Variables).
Sur la page Variables , cliquez sur l'onglet Create (Créer).
Sur la page Variable , saisissez les informations suivantes :
Key (Clé) : my_value
Val (Valeur) : example_value
Cliquez sur Enregistrer .
Configuration du modèle :
Configuration de l'affinité du pod
Lorsque vous configurez le paramètre affinity dans GKEStartPodOperator, vous contrôlez les nœuds sur lesquels les pods sont programmés, par exemple les nœuds d'un pool de nœuds spécifique. Lorsque vous avez créé votre cluster, vous avez créé deux pools de nœuds nommés pool-0 et pool-1. Cet opérateur indique que les pods ne doivent s'exécuter que dans pool-1.
Emplacement de lancement des pods Kubernetes dans Cloud Composer avec affinité de pod (cliquez pour agrandir)
Configuration complète
Cet exemple présente toutes les variables que vous pouvez configurer dans GKEStartPodOperator. Il n'est pas nécessaire de modifier le code pour que la tâche ex-all-configs réussisse.
Pour en savoir plus sur chaque variable, consultez la documentation de référence Airflow sur les opérateurs GKE .
Supprimer le cluster
Le code présenté ici supprime le cluster créé au début de ce guide.
Étapes suivantes
