***************************************** Kubernetes Metadata Module (mmkubernetes) ***************************************** =========================== =========================================================================== **Module Name:**  **mmkubernetes** **Author:** `Tomáš Heinrich` `Rich Megginson` =========================== =========================================================================== Purpose ======= This module is used to add `Kubernetes ` metadata to log messages logged by containers running in Kubernetes. It will add the namespace uuid, pod uuid, pod and namespace labels and annotations, and other metadata associated with the pod and namespace. .. note:: This **only** works with log files in `/var/log/containers/*.log` (docker `--log-driver=json-file`, or CRI-O log files), or with journald entries with message properties `CONTAINER_NAME` and `CONTAINER_ID_FULL` (docker `--log-driver=journald`), and when the application running inside the container writes logs to `stdout`/`stderr`. This **does not** currently work with other log drivers. For json-file and CRI-O logs, you must use the `imfile` module with the `addmetadata="on"` parameter, and the filename must match the liblognorm rules specified by the `filenamerules` (:ref:`param-mmkubernetes-filenamerules`) or `filenamerulebase` (:ref:`param-mmkubernetes-filenamerulebase`) parameter values. For journald logs, there must be a message property `CONTAINER_NAME` which matches the liblognorm rules specified by the `containerrules` (:ref:`param-mmkubernetes-containerrules`) or `containerrulebase` (:ref:`param-mmkubernetes-containerrulebase`) parameter values. The record must also have the message property `CONTAINER_ID_FULL`. This module is implemented via the output module interface. This means that mmkubernetes should be called just like an action. After it has been called, there will be two new message properties: `kubernetes` and `docker`. There will be subfields of each one for the various metadata items: `$!kubernetes!namespace_name` `$!kubernetes!labels!this-is-my-label`, etc. There is currently only 1 docker subfield: `$!docker!container_id`. See https://github.com/ViaQ/elasticsearch-templates/blob/master/namespaces/kubernetes.yml and https://github.com/ViaQ/elasticsearch-templates/blob/master/namespaces/docker.yml for more details. Configuration Parameters ======================== .. note:: Parameter names are case-insensitive; camelCase is recommended for readability. .. toctree:: :hidden: ../../reference/parameters/mmkubernetes-annotation-match ../../reference/parameters/mmkubernetes-allowunsignedcerts ../../reference/parameters/mmkubernetes-busyretryinterval ../../reference/parameters/mmkubernetes-cacheentryttl ../../reference/parameters/mmkubernetes-cacheexpireinterval ../../reference/parameters/mmkubernetes-containerrulebase ../../reference/parameters/mmkubernetes-containerrules ../../reference/parameters/mmkubernetes-de-dot ../../reference/parameters/mmkubernetes-de-dot-separator ../../reference/parameters/mmkubernetes-dstmetadatapath ../../reference/parameters/mmkubernetes-filenamerulebase ../../reference/parameters/mmkubernetes-filenamerules ../../reference/parameters/mmkubernetes-kubernetesurl ../../reference/parameters/mmkubernetes-skipverifyhost ../../reference/parameters/mmkubernetes-srcmetadatapath ../../reference/parameters/mmkubernetes-sslpartialchain ../../reference/parameters/mmkubernetes-tls-cacert ../../reference/parameters/mmkubernetes-tls-mycert ../../reference/parameters/mmkubernetes-tls-myprivkey ../../reference/parameters/mmkubernetes-token ../../reference/parameters/mmkubernetes-tokenfile Action Parameters ----------------- .. list-table:: :widths: 30 70 :header-rows: 1 * - Parameter - Summary * - :ref:`param-mmkubernetes-annotation-match` - .. include:: ../../reference/parameters/mmkubernetes-annotation-match.rst :start-after: .. summary-start :end-before: .. summary-end * - :ref:`param-mmkubernetes-allowunsignedcerts` - .. include:: ../../reference/parameters/mmkubernetes-allowunsignedcerts.rst :start-after: .. summary-start :end-before: .. summary-end * - :ref:`param-mmkubernetes-busyretryinterval` - .. include:: ../../reference/parameters/mmkubernetes-busyretryinterval.rst :start-after: .. summary-start :end-before: .. summary-end * - :ref:`param-mmkubernetes-cacheentryttl` - .. include:: ../../reference/parameters/mmkubernetes-cacheentryttl.rst :start-after: .. summary-start :end-before: .. summary-end * - :ref:`param-mmkubernetes-cacheexpireinterval` - .. include:: ../../reference/parameters/mmkubernetes-cacheexpireinterval.rst :start-after: .. summary-start :end-before: .. summary-end * - :ref:`param-mmkubernetes-containerrulebase` - .. include:: ../../reference/parameters/mmkubernetes-containerrulebase.rst :start-after: .. summary-start :end-before: .. summary-end * - :ref:`param-mmkubernetes-containerrules` - .. include:: ../../reference/parameters/mmkubernetes-containerrules.rst :start-after: .. summary-start :end-before: .. summary-end * - :ref:`param-mmkubernetes-de-dot` - .. include:: ../../reference/parameters/mmkubernetes-de-dot.rst :start-after: .. summary-start :end-before: .. summary-end * - :ref:`param-mmkubernetes-de-dot-separator` - .. include:: ../../reference/parameters/mmkubernetes-de-dot-separator.rst :start-after: .. summary-start :end-before: .. summary-end * - :ref:`param-mmkubernetes-dstmetadatapath` - .. include:: ../../reference/parameters/mmkubernetes-dstmetadatapath.rst :start-after: .. summary-start :end-before: .. summary-end * - :ref:`param-mmkubernetes-filenamerulebase` - .. include:: ../../reference/parameters/mmkubernetes-filenamerulebase.rst :start-after: .. summary-start :end-before: .. summary-end * - :ref:`param-mmkubernetes-filenamerules` - .. include:: ../../reference/parameters/mmkubernetes-filenamerules.rst :start-after: .. summary-start :end-before: .. summary-end * - :ref:`param-mmkubernetes-kubernetesurl` - .. include:: ../../reference/parameters/mmkubernetes-kubernetesurl.rst :start-after: .. summary-start :end-before: .. summary-end * - :ref:`param-mmkubernetes-skipverifyhost` - .. include:: ../../reference/parameters/mmkubernetes-skipverifyhost.rst :start-after: .. summary-start :end-before: .. summary-end * - :ref:`param-mmkubernetes-srcmetadatapath` - .. include:: ../../reference/parameters/mmkubernetes-srcmetadatapath.rst :start-after: .. summary-start :end-before: .. summary-end * - :ref:`param-mmkubernetes-sslpartialchain` - .. include:: ../../reference/parameters/mmkubernetes-sslpartialchain.rst :start-after: .. summary-start :end-before: .. summary-end * - :ref:`param-mmkubernetes-tls-cacert` - .. include:: ../../reference/parameters/mmkubernetes-tls-cacert.rst :start-after: .. summary-start :end-before: .. summary-end * - :ref:`param-mmkubernetes-tls-mycert` - .. include:: ../../reference/parameters/mmkubernetes-tls-mycert.rst :start-after: .. summary-start :end-before: .. summary-end * - :ref:`param-mmkubernetes-tls-myprivkey` - .. include:: ../../reference/parameters/mmkubernetes-tls-myprivkey.rst :start-after: .. summary-start :end-before: .. summary-end * - :ref:`param-mmkubernetes-token` - .. include:: ../../reference/parameters/mmkubernetes-token.rst :start-after: .. summary-start :end-before: .. summary-end * - :ref:`param-mmkubernetes-tokenfile` - .. include:: ../../reference/parameters/mmkubernetes-tokenfile.rst :start-after: .. summary-start :end-before: .. summary-end .. _mmkubernetes-statistic-counter: Statistic Counter ================= This plugin maintains per-action :doc:`statistics <../rsyslog_statistic_counter>`. The statistic is named "mmkubernetes($kubernetesurl)", where `$kubernetesurl` is the :ref:`param-mmkubernetes-kubernetesurl` setting for the action. Parameters are: - **recordseen** - number of messages seen by the action which the action has determined have Kubernetes metadata associated with them - **namespacemetadatasuccess** - the number of times a successful request was made to the Kubernetes API server for namespace metadata. - **namespacemetadatanotfound** - the number of times a request to the Kubernetes API server for namespace metadata was returned with a `404 Not Found` error code - the namespace did not exist at that time. - **namespacemetadatabusy** - the number of times a request to the Kubernetes API server for namespace metadata was returned with a `429 Busy` error code - the server was too busy to send a proper response. - **namespacemetadataerror** - the number of times a request to the Kubernetes API server for namespace metadata was returned with some other error code not handled above. These are typically "hard" errors which require some sort of intervention to fix e.g. Kubernetes server down, credentials incorrect. - **podmetadatasuccess** - the number of times a successful request was made to the Kubernetes API server for pod metadata. - **podmetadatanotfound** - the number of times a request to the Kubernetes API server for pod metadata was returned with a `404 Not Found` error code - the pod did not exist at that time. - **podmetadatabusy** - the number of times a request to the Kubernetes API server for pod metadata was returned with a `429 Busy` error code - the server was too busy to send a proper response. - **podmetadataerror** - the number of times a request to the Kubernetes API server for pod metadata was returned with some other error code not handled above. These are typically "hard" errors which require some sort of intervention to fix e.g. Kubernetes server down, credentials incorrect. - **podcachenumentries** - the number of entries in the pod metadata cache. - **namespacecachenumentries** - the number of entries in the namespace metadata cache. - **podcachehits** - the number of times a requested entry was found in the pod metadata cache. - **namespacecachehits** - the number of times a requested entry was found in the namespace metadata cache. - **podcachemisses** - the number of times a requested entry was not found in the pod metadata cache, and had to be requested from Kubernetes. - **namespacecachemisses** - the number of times a requested entry was not found in the namespace metadata cache, and had to be requested from Kubernetes. Fields ------ These are the fields added from the metadata in the json-file filename, or from the `CONTAINER_NAME` and `CONTAINER_ID_FULL` fields from the `imjournal` input: `$!kubernetes!namespace_name`, `$!kubernetes!pod_name`, `$!kubernetes!container_name`, `$!docker!id`, `$!kubernetes!master_url`. If mmkubernetes can extract the above fields from the input, the following fields will always be present. If they are not present, mmkubernetes failed to look up the namespace or pod in Kubernetes: `$!kubernetes!namespace_id`, `$!kubernetes!pod_id`, `$!kubernetes!creation_timestamp`, `$!kubernetes!host` The following fields may be present, depending on how the namespace and pod are defined in Kubernetes, and depending on the value of the directive `annotation_match`: `$!kubernetes!labels`, `$!kubernetes!annotations`, `$!kubernetes!namespace_labels`, `$!kubernetes!namespace_annotations` More fields may be added in the future. Error Handling -------------- If the plugin encounters a `404 Not Found` in response to a request for namespace or pod metadata, that is, the pod or namespace is missing, the plugin will cache that result, and no metadata will be available for that pod or namespace forever. If the pod or namespace is recreated, you will need to restart rsyslog in order to clear the cache and allow it to find that metadata. If the plugin gets a `429 Busy` response, the plugin will _not_ cache that result, and will _not_ add the metadata to the record. This can happen in very large Kubernetes clusters when you run into the upper limit on the number of concurrent Kubernetes API service connections. You may have to increase that limit. In the meantime, you can control what the plugin does with those records using the :ref:`param-mmkubernetes-busyretryinterval` setting. If you want to continue to process the records, but with incomplete metadata, set `busyretryinterval` to a non-zero value, which will be the number of seconds after which mmkubernetes will retry the connection. The default value is `5`, so by default, the plugin will retry the connection every `5` seconds. If the `429` error condition in the Kubernetes API server is brief and transient, this means you will have some (hopefully small) number of records without the metadata such as the uuids, labels, and annotations, but your pipeline will not stop. If the `429` error condition in the Kubernetes API server is persistent, it may require Kubernetes API server administrator intervention to address, and you may want to use the `busyretryinterval` value of `"0"`. This will cause the module to return a "hard" error (see below). For other errors, the plugin will assume they are "hard" errors requiring admin intervention, return an error code, and rsyslog will suspend the plugin. Use the :ref:`mmkubernetes-statistic-counter` to monitor for problems getting data from the Kubernetes API service. Example ------- Assuming you have an `imfile` input reading from docker json-file container logs managed by Kubernetes, with `addmetadata="on"` so that mmkubernetes can get the basic necessary Kubernetes metadata from the filename: .. code-block:: none input(type="imfile" file="/var/log/containers/*.log" tag="kubernetes" addmetadata="on") (Add `reopenOnTruncate="on"` if using Docker, not required by CRI-O). and/or an `imjournal` input for docker journald container logs annotated by Kubernetes: .. code-block:: none input(type="imjournal") Then mmkubernetes can be used to annotate log records like this: .. code-block:: none module(load="mmkubernetes") action(type="mmkubernetes") After this, you should have log records with fields described in the `Fields` section above. Credits ------- This work is based on https://github.com/fabric8io/fluent-plugin-kubernetes_metadata_filter and has many of the same features.