On September 15, 2026, all Cloud Composer 1 versions and versions 2.0.x of Cloud Composer 2 will reach their planned end of life. You will not be able to use environments with these versions. We recommend planning migration to Cloud Composer 3. Cloud Composer 2 versions 2.1.x and later are still supported and are not impacted by this change.
For information about scaling your environments, see
Scale environments.
Autoscaling environments
Cloud Composer 2 environments automatically scale in response to the demands
of your executed DAGs and tasks:
If your environment experiences a heavy load, Cloud Composer
automatically increases the number of workers in your environment.
If your environment does not use some of its workers, these workers are
removed to save environment resources and costs.
You can set the minimum and maximum number of workers for your environment.
Cloud Composer automatically scales your environment within the
set limits. You can adjust these limits at any time.
The number of workers is adjusted based on
the Scaling Factor Target metric. This metric is
calculated based on:
Current number of workers
Number of Celery tasks in the Celery queue, that are not assigned to a worker
Cloud Composer configures these autoscalers in the environment's
cluster. This automatically scales the number of nodes in the cluster, the
machine type and the number of workers.
Scale and performance parameters
In addition to autoscaling, you can control the scale and performance
parameters of your environment by adjusting the CPU, memory, and disk limits
for schedulers, web server, and workers. By doing so you can scale your
environment vertically, in addition to the horizontal scaling provided by the
autoscaling feature. You can adjust the scale and performance parameters of
Airflow schedulers, web server, and workers at any time.
The environment size performance parameter of your environment controls the
performance parameters of the managed Cloud Composer infrastructure
that includes the Airflow database. Consider selecting a larger environment
size if you want to run a large number of DAGs and tasks with higher
infrastructure performance. For example, larger environment's size increases
the amount of Airflow task log entries that your environment can process with
minimal delay.
Multiple schedulers
Airflow 2 can use more than one Airflow scheduler at the same time. This
Airflow feature is also known as the HA scheduler. In Cloud Composer 2,
you can set the number of schedulers for your environment and adjust it at any
time. Cloud Composer does not automatically scale the number of
schedulers in your environment.
For more information about configuring the number of schedulers for your
environment, see Scale environments.
Database disk space
Disk space for the Airflow database automatically increases to accommodate the
demand.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-25 UTC."],[[["\u003cp\u003eCloud Composer 2 environments automatically scale the number of workers based on the demands of executed DAGs and tasks, increasing workers during heavy loads and removing them during inactivity.\u003c/p\u003e\n"],["\u003cp\u003eThe environment's scaling is governed by the Scaling Factor Target metric, which considers the current worker count, queued tasks, idle workers, and the \u003ccode\u003ecelery.worker_concurrency\u003c/code\u003e Airflow setting.\u003c/p\u003e\n"],["\u003cp\u003eCloud Composer 2 utilizes three GKE autoscalers (Horizontal Pod Autoscaler, Cluster Autoscaler, and Node auto-provisioning) to automatically adjust the number of nodes, machine types, and workers in the environment's cluster.\u003c/p\u003e\n"],["\u003cp\u003eIn addition to autoscaling, users can manually adjust the CPU, memory, and disk limits for schedulers, web servers, and workers to vertically scale the environment, and they can also choose the environment size to control the managed Cloud Composer infrastructure.\u003c/p\u003e\n"],["\u003cp\u003eCloud Composer 2 allows for the configuration of multiple Airflow schedulers (HA scheduler) to be used simultaneously, but the number of schedulers is not automatically scaled by the system.\u003c/p\u003e\n"]]],[],null,["# Environment scaling\n\n[Cloud Composer 3](/composer/docs/composer-2/composer/docs/composer-3/environment-scaling \"View this page for Cloud Composer 3\") \\| **Cloud Composer 2** \\| [Cloud Composer 1](/composer/docs/composer-1/environment-scaling \"View this page for Cloud Composer 1\")\n\n\u003cbr /\u003e\n\n\u003cbr /\u003e\n\n\u003cbr /\u003e\n\n\u003cbr /\u003e\n\n\u003cbr /\u003e\n\n\u003cbr /\u003e\n\nThis page describes how environment scaling works in Cloud Composer 2.\n\nOther pages about scaling:\n\n- For a guide about selecting optimal scale and performance parameters for your environment, see [Optimize environment performance and costs](/composer/docs/composer-2/optimize-environments).\n- For information about scaling your environments, see [Scale environments](/composer/docs/composer-2/scale-environments).\n\nAutoscaling environments\n------------------------\n\nCloud Composer 2 environments automatically scale in response to the demands\nof your executed DAGs and tasks:\n\n- If your environment experiences a heavy load, Cloud Composer automatically increases the number of workers in your environment.\n- If your environment does not use some of its workers, these workers are removed to save environment resources and costs.\n- You can set the minimum and maximum number of workers for your environment. Cloud Composer automatically scales your environment within the set limits. You can adjust these limits at any time.\n\nThe number of workers is adjusted based on\nthe [Scaling Factor Target](/composer/docs/composer-2/monitor-environments#worker-metrics) metric. This metric is\ncalculated based on:\n\n- Current number of workers\n- Number of Celery tasks in the Celery queue, that are not assigned to a worker\n- Number of idle workers\n- `celery.worker_concurrency` Airflow configuration option\n\nCloud Composer autoscaling uses three different autoscalers\nprovided by GKE:\n\n- [Horizontal Pod Autoscaler (HPA)](/kubernetes-engine/docs/concepts/horizontalpodautoscaler)\n- [Cluster Autoscaler (CA)](/kubernetes-engine/docs/concepts/cluster-autoscaler)\n- [Node auto-provisioning (NAP)](/kubernetes-engine/docs/how-to/node-auto-provisioning)\n\nCloud Composer configures these autoscalers in the environment's\ncluster. This automatically scales the number of nodes in the cluster, the\nmachine type and the number of workers.\n\nScale and performance parameters\n--------------------------------\n\nIn addition to autoscaling, you can control the scale and performance\nparameters of your environment by adjusting the CPU, memory, and disk limits\nfor schedulers, web server, and workers. By doing so you can scale your\nenvironment vertically, in addition to the horizontal scaling provided by the\nautoscaling feature. You can adjust the scale and performance parameters of\nAirflow schedulers, web server, and workers at any time.\n\nThe *environment size* performance parameter of your environment controls the\nperformance parameters of the managed Cloud Composer infrastructure\nthat includes the Airflow database. Consider selecting a larger environment\nsize if you want to run a large number of DAGs and tasks with higher\ninfrastructure performance. For example, larger environment's size increases\nthe amount of Airflow task log entries that your environment can process with\nminimal delay.\n| **Note:** Environment size is different from the environment presets. Environment presets, which you can select when you create an environment, determine all limits, scale, and performance parameters of your environment, including the environment size. Environment size determines only the performance parameters of the managed Cloud Composer infrastructure of your environment.\n\nMultiple schedulers\n-------------------\n\nAirflow 2 can use more than one Airflow scheduler at the same time. This\nAirflow feature is also known as the **HA scheduler**. In Cloud Composer 2,\nyou can set the number of schedulers for your environment and adjust it at any\ntime. Cloud Composer does not automatically scale the number of\nschedulers in your environment.\n\nFor more information about configuring the number of schedulers for your\nenvironment, see [Scale environments](/composer/docs/composer-2/scale-environments#scheduler-count).\n\nDatabase disk space\n-------------------\n\nDisk space for the Airflow database automatically increases to accommodate the\ndemand.\n\n\nWhat's next\n-----------\n\n- [Scale environments](/composer/docs/composer-2/scale-environments)\n- [Cloud Composer pricing](/composer/pricing)\n- [Create environments](/composer/docs/composer-2/create-environments)\n- [Environment architecture](/composer/docs/composer-2/environment-architecture)"]]
