Amazon ECS Log File Locations - Amazon Elastic Container Service

Amazon ECS Log File Locations

Amazon ECS stores logs in the /var/log/ecs folder of your container instances. There are logs available from the Amazon ECS container agent and from the ecs-init service that controls the state of the agent (start/stop) on the container instance. You can view these log files by connecting to a container instance using SSH. For more information, see Connect to your container instance.

Note

If you are not sure how to collect all of the logs on your container instances, you can use the Amazon ECS logs collector. For more information, see Amazon ECS logs collector.

Amazon ECS Container Agent Log

The Amazon ECS container agent stores logs on your container instances.

For container agent version 1.36.0 and later, by default the logs are located at /var/log/ecs/ecs-agent.log on Linux instances and at C:\ProgramData\Amazon\ECS\log\ecs-agent.log on Windows instances.

For container agent version 1.35.0 and earlier, by default the logs are located at /var/log/ecs/ecs-agent.log.timestamp on Linux instances and at C:\ProgramData\Amazon\ECS\log\ecs-agent.log.timestamp on Windows instances.

By default, the agent logs are rotated hourly with a maximum of 24 logs being stored.

The following are the container agent configuration variables that can be used to change the default agent logging behavior. For more information, see Amazon ECS container agent configuration.

ECS_LOGFILE

Example values: /ecs-agent.log

Default value on Linux: Null

Default value on Windows: Null

The location where agent logs should be written. If you are running the agent via ecs-init, which is the default method when using the Amazon ECS-optimized AMI, the in-container path will be /log and ecs-init mounts that out to /var/log/ecs/ on the host.

ECS_LOGLEVEL

Example values: crit, error, warn, info, debug

Default value on Linux: info

Default value on Windows: info

The level of detail to log.

ECS_LOGLEVEL_ON_INSTANCE

Example values: none, crit, error, warn, info, debug

Default value on Linux: none, if ECS_LOG_DRIVER is explicitly set to a non-empty value; otherwise the same value as ECS_LOGLEVEL

Default value on Windows: none, if ECS_LOG_DRIVER is explicitly set to a non-empty value; otherwise the same value as ECS_LOGLEVEL

Can be used to override ECS_LOGLEVEL and set a level of detail that should be logged in the on-instance log file, separate from the level that is logged in the logging driver. If a logging driver is explicitly set, on-instance logs are turned off by default, but can be turned back on with this variable.

ECS_LOG_ROLLOVER_TYPE

Example values: size, hourly

Default value on Linux: hourly

Default value on Windows: hourly

Determines whether the container agent log file will be rotated hourly or based on size. By default, the agent log file is rotated each hour.

ECS_LOG_OUTPUT_FORMAT

Example values: logfmt, json

Default value on Linux: logfmt

Default value on Windows: logfmt

Determines the log output format. When the json format is used, each line in the log will be a structured JSON map.

ECS_LOG_MAX_FILE_SIZE_MB

Example values: 10

Default value on Linux: 10

Default value on Windows: 10

When the ECS_LOG_ROLLOVER_TYPE variable is set to size, this variable determines the maximum size (in MB) of the log file before it is rotated. If the rollover type is set to hourly, then this variable is ignored.

ECS_LOG_MAX_ROLL_COUNT

Example values: 24

Default value on Linux: 24

Default value on Windows: 24

Determines the number of rotated log files to keep. Older log files are deleted after this limit is reached.

For container agent version 1.36.0 and later, the following is an example log file when the logfmt format is used.

level=info time=2019-12-12T23:43:29Z msg="Loading configuration" module=agent.go level=info time=2019-12-12T23:43:29Z msg="Image excluded from cleanup: amazon/amazon-ecs-agent:latest" module=parse.go level=info time=2019-12-12T23:43:29Z msg="Image excluded from cleanup: amazon/amazon-ecs-pause:0.1.0" module=parse.go level=info time=2019-12-12T23:43:29Z msg="Amazon ECS agent Version: 1.36.0, Commit: ca640387" module=agent.go level=info time=2019-12-12T23:43:29Z msg="Creating root ecs cgroup: /ecs" module=init_linux.go level=info time=2019-12-12T23:43:29Z msg="Creating cgroup /ecs" module=cgroup_controller_linux.go level=info time=2019-12-12T23:43:29Z msg="Loading state!" module=statemanager.go level=info time=2019-12-12T23:43:29Z msg="Event stream ContainerChange start listening..." module=eventstream.go level=info time=2019-12-12T23:43:29Z msg="Restored cluster 'auto-robc'" module=agent.go level=info time=2019-12-12T23:43:29Z msg="Restored from checkpoint file. I am running as 'arn:aws:ecs:us-west-2:0123456789:container-instance/auto-robc/3330a8a91d15464ea30662d5840164cd' in cluster 'auto-robc'" module=agent.go

The following is an example log file when the JSON format is used.

{"time": "2019-11-07T22:52:02Z", "level": "info", "msg": "Starting Amazon Elastic Container Service Agent", "module": "engine.go"}

For container agent versions 1.35.0 and earlier, the following is the format of the log file.

2016-08-15T15:54:41Z [INFO] Starting Agent: Amazon ECS Agent - v1.12.0 (895f3c1) 2016-08-15T15:54:41Z [INFO] Loading configuration 2016-08-15T15:54:41Z [WARN] Invalid value for task cleanup duration, will be overridden to 3h0m0s, parsed value 0, minimum threshold 1m0s 2016-08-15T15:54:41Z [INFO] Checkpointing is enabled. Attempting to load state 2016-08-15T15:54:41Z [INFO] Loading state! module="statemanager" 2016-08-15T15:54:41Z [INFO] Detected Docker versions [1.17 1.18 1.19 1.20 1.21 1.22] 2016-08-15T15:54:41Z [INFO] Registering Instance with ECS 2016-08-15T15:54:41Z [INFO] Registered! module="api client"

Amazon ECS ecs-init Log

The ecs-init process stores logs at /var/log/ecs/ecs-init.log.

cat /var/log/ecs/ecs-init.log

Output:

2018-02-16T18:13:54Z [INFO] pre-start 2018-02-16T18:13:56Z [INFO] start 2018-02-16T18:13:56Z [INFO] No existing agent container to remove. 2018-02-16T18:13:56Z [INFO] Starting Amazon Elastic Container Service Agent

IAM Roles for Tasks Credential Audit Log

When the credential provider for the IAM role is used to provide credentials to tasks, these requests are saved in an audit log. The audit log inherits the same log rotation settings as the container agent log. The ECS_LOG_ROLLOVER_TYPE, ECS_LOG_MAX_FILE_SIZE_MB, and ECS_LOG_MAX_ROLL_COUNT container agent configuration variables can be set to affect the behavior of the audit log. For more information, see Amazon ECS Container Agent Log.

For container agent version 1.36.0 and later, the audit log is located at /var/log/ecs/audit.log. When the log is rotated, a timestamp in YYYY-MM-DD-HH format is added to the end of the log file name.

For container agent version 1.35.0 and earlier, the audit log is located at /var/log/ecs/audit.log.YYYY-MM-DD-HH.

The log entry format is as follows:

  • Timestamp

  • HTTP response code

  • IP address and port number of request origin

  • Relative URI of the credential provider

  • The user agent that made the request

  • The ARN of the task to which the requesting container belongs

  • The GetCredentials API name and version number

  • The name of the Amazon ECS cluster to which the container instance is registered

  • The container instance ARN

An example log entry is shown below.

cat /var/log/ecs/audit.log.2016-07-13-16

Output:

2016-07-13T16:11:53Z 200 172.17.0.5:52444 "/v1/credentials" "python-requests/2.7.0 CPython/2.7.6 Linux/4.4.14-24.50.amzn1.x86_64" TASK_ARN GetCredentials 1 CLUSTER_NAME CONTAINER_INSTANCE_ARN