Known issues

Cloud Composer 1 | Cloud Composer 2

This page lists known Cloud Composer issues. Some fixes for these issues are in-progress, and will be available in future versions.

Some issues affect older versions, and can be fixed by upgrading your environment.

Non-RFC 1918 address ranges are partially supported for Pods and Services

Cloud Composer depends on GKE to deliver support for non-RFC 1918 addresses for Pods and Services. Currently, only the following list of Non-RFC 1918 ranges is supported in Cloud Composer:


Airflow UI does not show tasks logs when DAG Serialization is on in Composer 1.10.2 and Composer 1.10.3

Enabling DAG serialization in environments using Composer versions 1.10.2 and 1.10.3 prevents logs from showing in the Airflow web server. Upgrade to version 1.10.4 (or later) to fix this issue.

GKE Workload Identity is not supported

This issue applies only to Cloud Composer 1 environments. Cloud Composer 2 environments use Workload Identity.

You cannot turn on Workload Identity for Cloud Composer environment clusters. As a result, you may see the WORKLOAD_IDENTITY_DISABLED finding in Security Command Center.

GKE Pod Security Policies are not supported

You cannot turn on GKE Pod Security Policies for Cloud Composer environment clusters. As a result, you may see the POD_SECURITY_POLICY_DISABLED finding in Security Command Center.

Environment labels added during an update are not fully propagated

Updated environment labels are not applied to Compute Engine VMs. As a workaround, those labels can be applied manually.

GKE upgrades in the context of CVE-2020-14386 problem

We are working on addressing the CVE-2020-14386 vulnerability for all Cloud Composer environments. As part of the fix, all existing Cloud Composer's GKE clusters will get updated to a newer version.

Customers that decide to address the vulnerability immediately, can upgrade Composer GKE Cluster by following these instructions with the following considerations:

Step 1. If you're running a Cloud Composer version earlier than 1.7.2 then upgrade to a newer version of Cloud Composer. If you already have version 1.7.2 or later, please, go to the next point.

Step 2. Upgrade GKE cluster (master and nodes) to the latest 1.15 patch version containing the fix for this vulnerability.

Airflow tasks logs are unavailable in the Airflow web server after upgrading from Airflow 1.9.0 to Airflow 1.10.x

Airflow 1.10.x introduced backwards-incompatible changes to the naming convention for log files. Zone information is now added to the log names for Airflow tasks.

Airflow 1.9.0 stores and expects the log names to be in the following format: BUCKET/logs/DAG/2020-03-30T10:29:06/1.log Airflow 1.10.x stores and expects the log names to be in the following format: BUCKET/logs/DAG/2020-03-30T10:29:06+00:00/1.log

As a result, if you upgrade from Airflow 1.9.0 to Airflow 1.10.x and would like to read the log for a task executed with Airflow 1.9.0, the Airflow Web server will show the following error message: Unable to read remote log from BUCKET/logs/DAG/2020-03-30T10:29:06+00:00/1.log

Workaround: Rename the logs generated by Airflow 1.9.0 in the Cloud Storage bucket using the format: BUCKET/logs/DAG/2020-03-30T10:29:06+00:00/1.log

Cannot create Cloud Composer environments with the organization policy constraints/compute.disableSerialPortLogging enforced

Cloud Composer environment creation will fail if constraints/compute.disableSerialPortLogging is enforced on the target project.


To determine if you're impacted by this issue, follow this procedure:

Go the GKE menu in Google Cloud console. Visit the GKE menu

Then, select your newly created cluster. Check for the following error:

Not all instances running in IGM after 123.45s.
Expect <number of desired instances in IGM>. Current errors:

Constraint constraints/compute.disableSerialPortLogging violated for
project <target project number>.


  1. Disable the organization policy on the project where the Cloud Composer environment will be created.

    An organization policy can always be disabled at the project level even if the parent resources (organization or folder) has it enabled. See the Customizing policies for boolean constraints page for more details.

  2. Use exclusion filters

    Using an exclusion filter for serial port logs. accomplishes the same goal as the disabling the org policy, as there will be serial console logs in Logging. For more details, see the Exclusion filters page.

Usage of Deployment Manager to manage GCP resources protected by VPC Service Controls

Composer uses Deployment Manager to create components of Cloud Composer environments.

In December 2020, you may have received information that you may need to perform additional VPC Service Controls configuration to be able to use Deployment Manager to manage resources protected by VPC Service Controls.

We would like to clarify that no action is required on your side if you are using Composer and you are not using Deployment Manager directly to manage GCP resources mentioned in the Deployment Manager's announcement.

Cannot delete an environment after its GKE cluster is deleted

If you delete your environment's cluster before the environment itself, then attempts to delete your environment result in the following error:

 Got error "" during CP_DEPLOYMENT_DELETING [Rerunning Task. ]

To delete an environment when its GKE cluster is already deleted:

  1. Open the Deployment Manager page in the Google Cloud console.

    Open the Deployment Manager page

  2. Find all deployments marked with labels:

    • goog-composer-environment:<environment-name>
    • goog-composer-location:<environment-location>.

    You should see two deployments that are marked with the described labels:

    • A deployment named <environment-location>-<environment-name-prefix>-<hash>-sd
    • A deployment named addons-<uuid>
  3. Manually delete resources that are still listed in these two deployments and exist in the project (for example, Pub/Sub topics and subscriptions). To do so:

    1. Select the deployments.

    2. Click Delete.

    3. Select the Delete 2 deployments and all resources created by them, such as VMs, load balancers and disks option and click Delete all.

    The deletion operation fails, but the leftover resources are deleted.

  4. Delete the deployments using one of these options:

    • In Google Cloud console, select both deployments again. Click Delete, then select the Delete 2 deployments, but keep resources created by them option.

    • Run a gcloud command to delete the deployments with the ABANDON policy:

      gcloud deployment-manager deployments delete addons-<uuid> \
      gcloud deployment-manager deployments delete <location>-<env-name-prefix>-<hash>-sd \
  5. Delete your Cloud Composer environment.

Deployment Manager displays information about an unsupported feature

You might see the following warning in the Deployment Manager tab:

The deployment uses actions, which are an unsupported feature. We recommend
that you avoid using actions.

For Deployment Manager's deployments owned by Cloud Composer, you can ignore this warning.

Warnings about duplicate entries of 'echo' task belonging to the 'echo-airflow_monitoring' DAG

You might see the following entry in the Airflow logs:

in _query db.query(q) File "/opt/python3.6/lib/python3.6/site-packages/MySQLdb/", line 280, in query _mysql.connection.query(self, query)
_mysql_exceptions.IntegrityError: (1062, "Duplicate entry
'echo-airflow_monitoring-2020-10-20 15:59:40.000000' for key 'PRIMARY'")

You can ignore these log entries, because this error doesn't impact Airflow DAG and task processing.

We work on improving Cloud Composer service to remove these warnings from Airflow logs.

Cloud Composer environment creation fails when the compute.requireOsLogin policy is enabled

If compute.requireOsLogin policy is set to true in your project, then Cloud Composer environment creation operations fails.

To create Cloud Composer environments, disable this policy in your project.

For more information about this organizational policy, see Organization policy constraints.

Cloud Composer environment creation fails when the compute.vmExternalIpAccess is disabled

Cloud Composer-owned GKE clusters configured in the Public IP mode require external connectivity for their VMs. Because of this, the compute.vmExternalIpAccess policy cannot forbid the creation of VMs with external IP addresses. For more information about this organizational policy, see Organization policy constraints.

Cloud Composer environment creation fails when the compute.vmCanIpForward policy is disabled

Cloud Composer 1 environments created in the non-VPC-Native (using alias IP) mode require this policy to allow the creation of VMs with the enabled "IP Forwarding" feature. For more information about this organizational policy, see Organization policy constraints.

First DAG run for an uploaded DAG file has several failed tasks

When you upload a DAG file, sometimes the first few tasks from the first DAG run for it fail with the Unable to read remote log... error. This problem happens because the DAG file is synchronized between your environment's bucket, Airflow workers, and Airflow schedulers of your environment. These synchronizations are done independently. If the scheduler gets the DAG file and schedules it to be executed by a worker, and if the worker does not have the DAG file yet, then the task execution fails.

As a workaround, Airflow 2 environments in Cloud Composer 1.17.0-preview.9 and later versions are configured to perform two retries for a failed task by default. If a task fails, it is retried twice with 5 minute intervals.

To use the workaround for this problem in Airflow 1, override the core-default_task_retries Airflow configuration option and set it to a number greater than or equal to 2.

Task fails with 'OSError: [Errno 5] Input/output error' in Airflow 1.10.15 or earlier versions

A bug in Airflow 1 versions causes tasks to be put to the Redis queue twice in some rare cases.

Sometimes it can lead to a race condition on the log file, and a subsequent task failure. Tasks fail with OSError: [Errno 5] Input/output error in Cloud Logging and Task is in the 'running' state which is not a valid state for execution. in the task attempt log.

This bug is fixed in Airflow 2. If you encounter this issue in Airflow 1 in a long-running task, increase the value of the [celery_broker_transport_options]visibility_timeout Airflow configuration option (the default value is 604800 for Composer 1.17.0, 21600 for older environments). For short-running tasks, consider adding additional retries to the affected tasks or migrating your environment to Airflow 2.

Dataproc/Dataflow operators fail with Negsignal.SIGSEGV

This is an intermittent issue of grcpio library, when used from a Celery worker. This issue affects Airflow 1.10.14 and later versions.

The workaround is to change the grpcio polling strategy by adding the following environment variable to your environment: GRPC_POLL_STRATEGY=epoll1. This workaround is already applied in Cloud Composer 1.17.1 and later versions.

Announcements about the removal of support for deprecated Beta APIs from GKE versions

Cloud Composer manages underlying Cloud Composer-owned GKE clusters. Unless you explicitly use such APIs in your DAGs and your code, you can ignore announcements about GKE API deprecations. Cloud Composer takes care of any migrations, if necessary.

GKE upgrades in the context of CVE-2021-25741 security issue

All existing Cloud Composer's GKE clusters will be auto-upgraded to newer GKE versions with a fix for the issues described in CVE-2021-25741.

If you want to address this vulnerability immediately, upgrade the GKE cluster of your environment by following the instructions for upgrading a cluster,

  • If you have a Cloud Composer 1 environment and GKE version 1.18.x or earlier then upgrade to 1.18.20-gke.4501.

  • If you have a Cloud Composer 1 environment and GKE version 1.19.x then upgrade to 1.19.14-gke.301.

  • If you have a Cloud Composer 2 environment and GKE version 1.21.x then upgrade to 1.21.4-gke.301.

Cloud Composer should not be impacted by Apache Log4j 2 Vulnerability (CVE-2021-44228)

In response to Apache Log4j 2 Vulnerability (CVE-2021-44228), Cloud Composer has conducted a detailed investigation and we believe that Cloud Composer is not vulnerable to this exploit.

Cloud Composer 2: Airflow workers or schedulers might experience issues when accessing Cloud Storage buckets

In some sporadical situations, in case of Cloud Composer 2 environments when Airflow worker or Airflow scheduler is restarted then it may malfunction and experience issues when accessing Cloud Storage bucket content.

In such a situation, you might see errors starting with: Transport endpoint is not connected in Airflow logs.

For example, error log for Airflow worker might look like this:

[Errno 107] Transport endpoint is not connected: '/home/airflow/gcs/logs/airflow_monitoring/echo/2022-01-11T22:50:48+00:00'


  • If you use a preview version of Cloud Composer 2, please, upgrade to GA version of Cloud Composer 2: composer-2.0.18-airflow-2.2.5

  • If you experience problems when using composer-2.0.0 version then

    • you can upgrade to composer-2.0.18-airflow-2.2.5

    • trigger restart of Airflow components via installation of some PyPI dependency

Airflow UI might sometimes not re-load a plugin once it is changed

If a plugin consists of many files that import other modules, then the Airflow UI might not be able to recognize the fact that a plugin should be re-loaded. In such a case, one needs to trigger a restart of the Airflow webserver. You can do that by adding an environment variable or via installation or uninstallation of PYPI dependencies. You can also restart the Airflow web server.

Intermittent issues when communicating to Airflow Metedata Database

This known issue applies only to Cloud Composer 1.

Some older Cloud Composer 1 environments (1.16.3 or earlier) created before August 12, 2021 might experience transient issues related to communication to Airflow Metadata DBs.

If you experience this issue then in the Airflow tasks logs you will see the following error message:

"Can't connect to MySQL server on 'airflow-sqlproxy-service.default.svc.cluster.local' (104)"

Cloud Composer team works on resolving this problem. In the meantime, if you believe that you are highly impacted by this issue you can do the following to eliminate it:

  1. In Google Cloud console, go to the Environment Configuration page of the impacted Cloud Composer environments.
  2. Follow the view cluster details page to navigate to underlying GKE cluster.
  3. Navigate to the Nodes tab and click on the default-pool visible in Node Pools section. select default-pool
  4. Click Edit at the top of the page.
  5. Change the image version to be COS with Containered and save the configuration as it was presented below. Change Node Pool runtime from Docker to ContainerD
  6. Once accept the change, your default-pool will be reconfigured to use containered as node pool runtime. Some of your Airflow Tasks might fail while your default-pool will be reconfigured. The tasks should be re-run by Airflow if you have retries configured in your Airflow environment.

The environment's cluster has workloads in the Unschedulable state

This known issue applies only to Cloud Composer 2.

In Cloud Composer 2, after an environment is created, several workloads in the environment's cluster remain in the Unschedulable state. This is a known issue. Unschedulable DaemonSet workloads named composer-gcsfuse and composer-fluentd do not affect your environment.

Error 504 when accessing the Airflow UI

You can get the 504 Gateway Timeout error when accessing the Airflow UI. This error can have several causes:

  • Transient communication issue. In this case, attempt to access the Airflow UI later.
  • (Cloud Composer 2 only) Connectivity issue. If Airflow UI is permanently unavailable, and timeout or 504 errors are generated, make sure that your environment can access * If you use Private Google Access and send traffic over Virtual IPs, or VPC Service Controls and send traffic over Virtual IPs, make sure that your Cloud DNS is configured also for * domain names.
  • Unresponsive Airflow web server. If the error 504 persists, but you can still access the Airflow UI at certain times, then the Airflow web server might be unresponsive because it's overwhelmed. Attempt to increase the scale and performance parameters of the web server.

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