diff --git a/content/config/containers/logging/configure.md b/content/config/containers/logging/configure.md index 80f777c3d6f..ce037643d8e 100644 --- a/content/config/containers/logging/configure.md +++ b/content/config/containers/logging/configure.md @@ -198,14 +198,6 @@ see more options. | [`gcplogs`](gcplogs.md) | Writes log messages to Google Cloud Platform (GCP) Logging. | | [`logentries`](logentries.md) | Writes log messages to Rapid7 Logentries. | -> **Note** -> -> When using Docker Engine 19.03 or older, the [`docker logs` command](../../../engine/reference/commandline/logs.md) -> is only functional for the `local`, `json-file` and `journald` logging drivers. -> Docker 20.10 and up introduces "dual logging", which uses a local buffer that -> allows you to use the `docker logs` command for any logging driver. Refer to -> [reading logs when using remote logging drivers](dual-logging.md) for details. - ## Limitations of logging drivers - Reading log information requires decompressing rotated log files, which causes diff --git a/content/config/containers/logging/dual-logging.md b/content/config/containers/logging/dual-logging.md index 54620ce3adc..e2a193e9792 100644 --- a/content/config/containers/logging/dual-logging.md +++ b/content/config/containers/logging/dual-logging.md @@ -1,46 +1,30 @@ --- -description: +description: > Learn how to read container logs locally when using a third party logging solution. -keywords: - docker, logging, driver, dual logging, dual-logging, cache, ring-buffer, +keywords: > + docker, logging, driver, dual logging, dual logging, cache, ring-buffer, configuration title: Use docker logs with remote logging drivers --- ## Overview -Prior to Docker Engine 20.10, the [`docker logs` command](../../../engine/reference/commandline/logs.md) -could only be used with logging drivers that supported for containers using the -`local`, `json-file`, or `journald` log drivers. However, many third party logging -drivers had no support for locally reading logs using `docker logs` - -This created multiple problems when attempting to gather log data in an -automated and standard way. Log information could only be accessed and viewed -through the third-party solution in the format specified by that -third-party tool. - -Starting with Docker Engine 20.10, you can use `docker logs` to read container -logs regardless of the configured logging driver or plugin. This capability, -referred to as "dual logging", allows you to use `docker logs` to read container -logs locally in a consistent format, regardless of the log driver used, because -the engine is configured to log information to the “local” logging driver. Refer -to [Configure the default logging driver](configure.md) for additional information. - -Dual logging uses the [`local`](local.md) logging driver to act as cache for -reading the latest logs of your containers. By default, the cache has log-file -rotation enabled, and is limited to a maximum of 5 files of 20MB each (before +You can use the `docker logs` command to read container logs regardless of the +configured logging driver or plugin. Docker Engine uses the [`local`](local.md) +logging driver to act as cache for reading the latest logs of your containers. +This is called dual logging. By default, the cache has log-file rotation +enabled, and is limited to a maximum of 5 files of 20 MB each (before compression) per container. Refer to the [configuration options](#configuration-options) section to customize -these defaults, or to the [disable dual-logging](#disable-the-dual-logging-cache) +these defaults, or to the [disable dual logging](#disable-the-dual-logging-cache) section to disable this feature. ## Prerequisites -No configuration changes are needed to use dual logging. Docker Engine 20.10 and -up automatically enable dual logging if the configured logging driver doesn't -support reading logs. +Docker Engine automatically enables dual logging if the configured logging +driver doesn't support reading logs. The following examples show the result of running a `docker logs` command with and without dual logging availability: @@ -124,7 +108,7 @@ as a default, with dual logging caching enabled: ### Configuration options -The "dual logging" cache accepts the same configuration options as the +The dual logging cache accepts the same configuration options as the [`local` logging driver](local.md), but with a `cache-` prefix. These options can be specified per container, and defaults for new containers can be set using the [daemon configuration file](/engine/reference/commandline/dockerd/#daemon-configuration-file). diff --git a/content/config/containers/logging/gcplogs.md b/content/config/containers/logging/gcplogs.md index 5a130e84f0c..4eb1fe719d3 100644 --- a/content/config/containers/logging/gcplogs.md +++ b/content/config/containers/logging/gcplogs.md @@ -40,8 +40,6 @@ You can set the logging driver for a specific container by using the $ docker run --log-driver=gcplogs ... ``` -The `docker logs` command isn't available for this logging driver. - If Docker detects that it's running in a Google Cloud Project, it discovers configuration from the [instance metadata service](https://cloud.google.com/compute/docs/metadata).