fluent-plugin-kubernetes_sumologic

This page describes the Sumo Kubernetes Fluentd plugin.

Support

The code in this repository has been developed in collaboration with the Sumo Logic community and is not supported via standard Sumo Logic Support channels. For any issues or questions please submit an issue within the GitHub repository. The maintainers of this project will work directly with the community to answer any questions, address bugs, or review any requests for new features.

Installation

The plugin runs as a Kubernetes DaemonSet; it runs an instance of the plugin on each host in a cluster. Each plugin instance pulls system, kubelet, docker daemon, and container logs from the host and sends them, in JSON or text format, to an HTTP endpoint on a hosted collector in the Sumo service. Note the plugin with default configuration requires Kubernetes >=1.8. See the section below on running this on Kubernetes <1.8

• Step 1 Create hosted collector and HTTP source in Sumo
• Step 2 Create a Kubernetes secret
• Step 3 Install the Sumo Kubernetes FluentD plugin
  • Option A Install plugin using kubectl
  • Option B Helm chart
• Environment variables
  • Override environment variables using annotations
  • Exclude data using annotations
  • Include excluded using annotations
• Step 4 Set up Heapster for metric collection
  • Kubernetes ConfigMap
  • Kubernetes Service
  • Kubernetes Deployment
• Log data
  • Docker
  • Kubelet
  • Containers
• Taints and Tolerations
• Running On OpenShift

Step 1 Create hosted collector and HTTP source in Sumo

In this step you create, on the Sumo service, an HTTP endpoint to receive your logs. This process involves creating an HTTP source on a hosted collector in Sumo. In Sumo, collectors use sources to receive data.

1. If you don’t already have a Sumo account, you can create one by clicking the Free Trial button on https://www.sumologic.com/.
2. Create a hosted collector, following the instructions on Configure a Hosted Collector in Sumo help. (If you already have a Sumo hosted collector that you want to use, skip this step.)
3. Create an HTTP source on the collector you created in the previous step. For instructions, see HTTP Logs and Metrics Source in Sumo help.
4. When you have configured the HTTP source, Sumo will display the URL of the HTTP endpoint. Make a note of the URL. You will use it when you configure the Kubernetes service to send data to Sumo.

Step 2 Create a Kubernetes secret

Create a secret in Kubernetes with the HTTP source URL. If you want to change the secret name, you must modify the Kubernetes manifest accordingly.

kubectl create secret generic sumologic --from-literal=collector-url=INSERT_HTTP_URL

You should see the confirmation message

secret "sumologic" created.

Step 3 Install the Sumo Kubernetes FluentD plugin

Follow the instructions in Option A below to install the plugin using kubectl. If you prefer to use a Helm chart, see Option B.

Before you start, see Environment variables for information about settings you can customize, and how to use annotations to override selected environment variables and exclude data from being sent to Sumo.

Option A Install plugin using kubectl

See the sample Kubernetes DaemonSet and Role in fluentd.yaml.

1. Clone the GitHub repo.

2. In fluentd-kubernetes-sumologic, install the chart using kubectl.

Which .yaml file you should use depends on whether or not you are running RBAC for authorization. RBAC is enabled by default as of Kubernetes 1.6. Note the plugin with default configuration requires Kubernetes >=1.8. See the section below on running this on Kubernetes <1.8

Non-RBAC (Kubernetes 1.5 and below)

kubectl create -f /daemonset/nonrbac/fluentd.yaml

RBAC (Kubernetes 1.6 and above)

kubectl create -f /daemonset/rbac/fluentd.yaml

Note if you modified the command in Step 2 to use a different name, update the .yaml file to use the correct secret.

Logs should begin flowing into Sumo within a few minutes of plugin installation.

Option B Helm chart

If you use Helm to manage your Kubernetes resources, there is a Helm chart for the plugin at https://github.com/kubernetes/charts/tree/master/stable/sumologic-fluentd.

Environment variables

Environment	Variable Description
AUDIT_LOG_PATH	Define the path to the Kubernetes Audit Log Default: /mnt/log/kube-apiserver-audit.log
CONCAT_SEPARATOR	The character to use to delimit lines within the final concatenated message. Most multi-line messages contain a newline at the end of each line. Default: ""
EXCLUDE_CONTAINER_REGEX	A regular expression for containers. Matching containers will be excluded from Sumo. The logs will still be sent to FluentD.
EXCLUDE_FACILITY_REGEX	A regular expression for syslog facilities. Matching facilities will be excluded from Sumo. The logs will still be sent to FluentD.
EXCLUDE_HOST_REGEX	A regular expression for hosts. Matching hosts will be excluded from Sumo. The logs will still be sent to FluentD.
EXCLUDE_NAMESPACE_REGEX	A regular expression for namespaces. Matching namespaces will be excluded from Sumo. The logs will still be sent to FluentD.
EXCLUDE_PATH	Files matching this pattern will be ignored by the in_tail plugin, and will not be sent to Kubernetes or Sumo. This can be a comma-separated list as well. See in_tail documentation for more information. For example, defining EXCLUDE_PATH as shown below excludes all files matching /var/log/containers/*.log, ... env:   - name: EXCLUDE_PATH   value: "[\"/var/log/containers/*.log\"]"
EXCLUDE_POD_REGEX	A regular expression for pods. Matching pods will be excluded from Sumo. The logs will still be sent to FluentD.
EXCLUDE_PRIORITY_REGEX	A regular expression for syslog priorities. Matching priorities will be excluded from Sumo. The logs will still be sent to FluentD.
EXCLUDE_UNIT_REGEX	A regular expression for systemd units. Matching units will be excluded from Sumo. The logs will still be sent to FluentD.
FLUENTD_SOURCE	Fluentd can use log tail, systemd query or forward as the source, Allowable values: file, systemd, forward. Default: file
FLUENTD_USER_CONFIG_DIR	A directory of user-defined fluentd configuration files, which must be in the *.conf directory in the container.
FLUSH_INTERVAL	How frequently to push logs to Sumo. Default: 5s
KUBERNETES_META	Include or exclude Kubernetes metadata such as namespace and pod_name if using JSON log format. Default: true
KUBERNETES_META_REDUCE	Reduces redundant Kubernetes metadata, see Reducing Kubernetes Metadata. Default: false
LOG_FORMAT	Format in which to post logs to Sumo. Allowable values: text—Logs will appear in SumoLogic in text format. json—Logs will appear in SumoLogic in json format. json_merge—Same as json but if the container logs in json format to stdout it will merge in the container json log at the root level and remove the log field. Default: json
MULTILINE_START_REGEXP	The regular expression for the concat plugin to use when merging multi-line messages. Defaults to Julian dates, for example, Jul 29, 2017.
NUM_THREADS	Set the number of HTTP threads to Sumo. It might be necessary to do so in heavy-logging clusters. Default: 1
READ_FROM_HEAD	Start to read the logs from the head of file, not bottom. Only applies to containers log files. See in_tail doc for more information. Default: true
SOURCE_CATEGORY	Set the _sourceCategory metadata field in Sumo. Default: "%{namespace}/%{pod_name}"
SOURCE_CATEGORY_PREFIX	Prepends a string that identifies the cluster to the _sourceCategory metadata field in Sumo. Default: kubernetes/
SOURCE_CATEGORY_REPLACE_DASH	Used to replace a dash (-) character with another character. Default: / For example, a Pod called travel-nginx-3629474229-dirmo within namespace app will appear in Sumo with _sourceCategory=app/travel/nginx.
SOURCE_HOST	Set the _sourceHost metadata field in Sumo. Default: ""
SOURCE_NAME	Set the _sourceName metadata field in Sumo. Default: "%{namespace}.%{pod}.%{container}"
TIME_KEY	The field name for json formatted sources that should be used as the time. See time_key. Default: time
ADD_TIMESTAMP	Option to control adding timestamp to logs. Default: true
TIMESTAMP_KEY	Field name when add_timestamp is on. Default: timestamp
ADD_STREAM	Option to control adding stream to logs. Default: true
ADD_TIME	Option to control adding time to logs. Default: true
CONTAINER_LOGS_PATH	Specify the path in_tail should watch for container logs. Default: /mnt/log/containers/*.log
PROXY_URI	Add the uri of the proxy environment if present.
ENABLE_STAT_WATCHER	Option to control the enabling of stat_watcher. Default: true
K8S_METADATA_FILTER_WATCH	Option to control the enabling of metadata filter plugin watch. Default: true
K8S_METADATA_FILTER_CA_FILE	Option to control the enabling of metadata filter plugin ca_file.
K8S_METADATA_FILTER_VERIFY_SSL	Option to control the enabling of metadata filter plugin verify_ssl. Default: true
K8S_METADATA_FILTER_CLIENT_CERT	Option to control the enabling of metadata filter plugin client_cert.
K8S_METADATA_FILTER_CLIENT_KEY	Option to control the enabling of metadata filter plugin client_key.
K8S_METADATA_FILTER_BEARER_TOKEN_FILE	Option to control the enabling of metadata filter plugin bearer_token_file.
K8S_METADATA_FILTER_BEARER_CACHE_SIZE	Option to control the enabling of metadata filter plugin cache_size. Default: 1000
K8S_METADATA_FILTER_BEARER_CACHE_TTL	Option to control the enabling of metadata filter plugin cache_ttl. Default: 3600
K8S_NODE_NAME	If set, improves caching of pod metadata and reduces API calls.
VERIFY_SSL	Verify ssl certificate of sumologic endpoint. Default: true
FORWARD_INPUT_BIND	The bind address to listen to if using forward as FLUENTD_SOURCE. Default: 0.0.0.0 (all addresses)
FORWARD_INPUT_PORT	The port to listen to if using forward as FLUENTD_SOURCE. Default: 24224

The following table show which environment variables affect which Fluentd sources.

Environment Variable	Containers	Docker	Kubernetes	Systemd
EXCLUDE_CONTAINER_REGEX	✔	✘	✘	✘
EXCLUDE_FACILITY_REGEX	✘	✘	✘	✔
EXCLUDE_HOST_REGEX	✔	✘	✘	✔
EXCLUDE_NAMESPACE_REGEX	✔	✘	✔	✘
EXCLUDE_PATH	✔	✔	✔	✘
EXCLUDE_PRIORITY_REGEX	✘	✘	✘	✔
EXCLUDE_POD_REGEX	✔	✘	✘	✘
EXCLUDE_UNIT_REGEX	✘	✘	✘	✔
TIME_KEY	✔	✘	✘	✘

FluentD stops processing logs

When dealing with large volumes of data (TB's from what we have seen), FluentD may stop processing logs, but continue to run. This issue seems to be caused by the scalability of the inotify process that is packaged with the FluentD in_tail plugin. If you encounter this situation, setting the ENABLE_STAT_WATCHER to false should resolve this issue.

Reducing Kubernetes metadata

You can use the KUBERNETES_META_REDUCE environment variable (global) or the sumologic.com/kubernetes_meta_reduce annotation (per pod) to reduce the amount of Kubernetes metadata included with each log line under the kubernetes field.

When set, FluentD will remove the following properties:

• pod_id
• container_id
• namespace_id
• master_url
• labels
• annotations

Logs will still include:

• pod_name
• container_name
• namespace_name
• host

These fields still allow you to uniquely identify a pod and look up additional details with the Kubernetes API.

apiVersion: v1
kind: ReplicationController
metadata:
  name: nginx
spec:
  replicas: 1
  selector:
    app: mywebsite
  template:
    metadata:
      name: nginx
      labels:
        app: mywebsite
      annotations:
        sumologic.com/kubernetes_meta_reduce: "true"
    spec:
      containers:
      - name: nginx
        image: nginx
        ports:
        - containerPort: 80

Override environment variables using annotations

You can override the LOG_FORMAT, KUBERNETES_META_REDUCE, SOURCE_CATEGORY and SOURCE_NAME environment variables, per pod, using Kubernetes annotations. For example:

apiVersion: v1
kind: ReplicationController
metadata:
  name: nginx
spec:
  replicas: 1
  selector:
    app: mywebsite
  template:
    metadata:
      name: nginx
      labels:
        app: mywebsite
      annotations:
        sumologic.com/format: "text"
        sumologic.com/kubernetes_meta_reduce: "true"
        sumologic.com/sourceCategory: "mywebsite/nginx"
        sumologic.com/sourceName: "mywebsite_nginx"
    spec:
      containers:
      - name: nginx
        image: nginx
        ports:
        - containerPort: 80

Exclude data using annotations

You can also use the sumologic.com/exclude annotation to exclude data from Sumo. This data is sent to FluentD, but not to Sumo.

apiVersion: v1
kind: ReplicationController
metadata:
  name: nginx
spec:
  replicas: 1
  selector:
    app: mywebsite
  template:
    metadata:
      name: nginx
      labels:
        app: mywebsite
      annotations:
        sumologic.com/format: "text"
        sumologic.com/sourceCategory: "mywebsite/nginx"
        sumologic.com/sourceName: "mywebsite_nginx"
        sumologic.com/exclude: "true"
    spec:
      containers:
      - name: nginx
        image: nginx
        ports:
        - containerPort: 80

Include excluded using annotations

If you excluded a whole namespace, but still need one or few pods to be still included for shipping to Sumologic, you can use the sumologic.com/include annotation to include data to Sumo. It takes precedence over the exclusion described above.

apiVersion: v1
kind: ReplicationController
metadata:
  name: nginx
spec:
  replicas: 1
  selector:
    app: mywebsite
  template:
    metadata:
      name: nginx
      labels:
        app: mywebsite
      annotations:
        sumologic.com/format: "text"
        sumologic.com/sourceCategory: "mywebsite/nginx"
        sumologic.com/sourceName: "mywebsite_nginx"
        sumologic.com/include: "true"
    spec:
      containers:
      - name: nginx
        image: nginx
        ports:
        - containerPort: 80

Step 4 Set up Heapster for metric collection

The recommended way to collect metrics from Kubernetes clusters is to use Heapster and a Sumo collector with a Graphite source.

Heapster aggregates metrics across a Kubenetes cluster. Heapster runs as a pod in the cluster, and discovers all nodes in the cluster and queries usage information from each node's kubelet—the on-machine Kubernetes agent.

Heapster provides metrics at the cluster, node and pod level.

1. Install Heapster in your Kubernetes cluster and configure a Graphite Sink to send the data in Graphite format to Sumo. For instructions, see https://github.com/kubernetes/heapster/blob/master/docs/sink-configuration.md#graphitecarbon. Assuming you have used the below YAML files to configure your system, then the sink option in graphite would be --sink=graphite:tcp://sumo-graphite.kube-system.svc:2003. You may need to change this depending on the namespace you run the deployment in, the name of the service or the port number for your Graphite source.

2. Use the Sumo Docker container. For instructions, see https://hub.docker.com/r/sumologic/collector/.

3. The following sections contain an example configmap, which contains the sources.json configuration, an example service, and an example deployment. Create these manifests in Kubernetes using kubectl.

Kubernetes ConfigMap

kind: ConfigMap
apiVersion: v1
metadata:
  name: "sumo-sources"
data:
  sources.json: |-
    {
      "api.version": "v1",
      "sources": [
        {
          "name": "SOURCE_NAME",
          "category": "SOURCE_CATEGORY",
          "automaticDateParsing": true,
          "contentType": "Graphite",
          "timeZone": "UTC",
          "encoding": "UTF-8",
          "protocol": "TCP",
          "port": 2003,
          "sourceType": "Graphite"
        }
      ]
    }

Kubernetes Service

apiVersion: v1
kind: Service
metadata:
  name: sumo-graphite
spec:
  ports:
    - port: 2003
  selector:
    app: sumo-graphite

Kubernetes Deployment

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  labels:
    app: sumo-graphite
  name: sumo-graphite
spec:
  replicas: 2
  template:
    metadata:
      labels:
        app: sumo-graphite
    spec:
      volumes:
      - name: sumo-sources
        configMap:
          name: sumo-sources
          items:
          - key: sources.json
            path: sources.json
      containers:
      - name: sumo-graphite
        image: sumologic/collector:latest
        ports:
        - containerPort: 2003
        volumeMounts:
        - mountPath: /sumo
          name: sumo-sources
        env:
        - name: SUMO_ACCESS_ID
          value: <SUMO_ACCESS_ID>
        - name: SUMO_ACCESS_KEY
          value: <SUMO_ACCESS_KEY>
        - name: SUMO_SOURCES_JSON
          value: /sumo/sources.json

Templating Kubernetes metadata

The following Kubernetes metadata is available for string templating:

String template	Description
%{namespace}	Namespace name
%{pod}	Full pod name (e.g. travel-products-4136654265-zpovl)
%{pod_name}	Friendly pod name (e.g. travel-products)
%{pod_id}	The pod's uid (a UUID)
%{container}	Container name
%{source_host}	Host
%{label:foo}	The value of label foo

Missing labels

Unlike the other templates, labels are not guaranteed to exist, so missing labels interpolate as "undefined".

For example, if you have only the label app: travel but you define SOURCE_NAME="%{label:app}@%{label:version}", the source name will appear as travel@undefined.

Log data

After performing the configuration described above, your logs should start streaming to SumoLogic in json or text format with the appropriate metadata. If you are using json format you can auto extract fields, for example _sourceCategory=some/app | json auto.

Docker

Kubelet

Note that Kubelet logs are only collected if you are using systemd. Kubernetes no longer outputs the kubelet logs to a file.

Containers

Taints and Tolerations

By default, the fluentd pods will schedule on, and therefore collect logs from, any worker nodes that do not have a taint and any master node that does not have a taint beyond the default master taint. If you would like to schedule pods on all nodes, regardless of taints, uncomment the following line from fluentd.yaml before applying it.

tolerations:
           #- operator: "Exists"

Running On OpenShift

This daemonset setting mounts /var/log as service account FluentD so you need to run containers as privileged container. Here is command example:

oc adm policy add-scc-to-user privileged system:serviceaccount:logging:fluentd
oc adm policy add-cluster-role-to-user cluster-reader system:serviceaccount:logging:fluentd
oc label node —all logging-sumologic-fluentd=true
oc patch ds fluentd-sumologic -p "spec:
  template:
    spec:
      containers:
      - image: sumologic/fluentd-kubernetes-sumologic:latest
        name: fluentd
        securityContext:
          privileged: true"
oc delete pod -l name = fluentd-sumologic

Running on Kubernetes versions <1.8

In order to run this plugin on Kubernetes <1.8 you will need to make some changes the yaml file prior to deploying it.

Replace:

      - name: pos-files
        hostPath:
          path: /var/run/fluentd-pos
          type: ""

With:

      - name: pos-files
        emptyDir: {}

Output to S3

If you need to also send data to S3 (i.e. as a secondary backup/audit trail) the image includes the fluent-plugin-s3 plugin. In order to send the logs from FluentD to multiple outputs, you must use the copy plugin. This image comes with an OOB configuration to output the logs to Sumo Logic. In order to output to multiple destinations, you need to modify that existing configuration.

Example: Send all logs to S3 and Sumo:

<match **>
  @type copy
  <store>
    @type sumologic
    log_key log
    endpoint "#{ENV['COLLECTOR_URL']}"
    verify_ssl "#{ENV['VERIFY_SSL']}"
    log_format "#{ENV['LOG_FORMAT']}"
    flush_interval "#{ENV['FLUSH_INTERVAL']}"
    num_threads "#{ENV['NUM_THREADS']}"
    open_timeout 60
    add_timestamp "#{ENV['ADD_TIMESTAMP']}"
    proxy_uri "#{ENV['PROXY_URI']}"
  </store>
  <store>
    @type s3
  
    aws_key_id YOUR_AWS_KEY_ID
    aws_sec_key YOUR_AWS_SECRET_KEY
    s3_bucket YOUR_S3_BUCKET_NAME
    s3_region us-west-1
    path logs/
    buffer_path /var/log/fluent/s3
  
    time_slice_format %Y%m%d%H
    time_slice_wait 10m
    utc
  
    buffer_chunk_limit 256m
  </store>
</match>

You can replace the OOB configuration by creating a new Docker image from our image or by using a configmap to inject the new configuration to the pod.

More details about the S3 plugin can be found in the docs.

Upgrading to v2.0.0

In version 2.0.0, some legacy FluentD configuration has been removed that could lead to duplicate logs being ingested into Sumo Logic. These logs were control plane components. This version was done as a major release as it breaks the current version of the Kubernetes App you may have installed in Sumo Logic.

After upgrading to this version, you will need to reinstall the Kubernetes App in Sumo Logic. If you do not some of the panels in the dashboards will not render properly.

If you have other content outside the app (Partitions, Scheduled Views, Field Extraction Rules or Scheduled Searches and Alerts), these may need to be updated after upgrading to v2.0.0. The logs, while the same content, have a different format and the same parsing logic and metadata may not apply.

The previous log format that is removed in v2.0.0:

{
   "timestamp": 1538776281387,
   "severity": "I",
   "pid": "1",
   "source": "wrap.go:42",
   "message": "GET /api/v1/namespaces/kube-system/endpoints/kube-scheduler: (3.514372ms) 200 [[kube-scheduler/v1.10.5 (linux/amd64) kubernetes/32ac1c9/leader-election] 127.0.0.1:46290]"
}

Is replaced by the following version. It is the same log line in a different format enriched with the same metadata the plugin applies to all pod logs.

{
   "timestamp": 1538776282152,
   "log": "I1005 21:51:21.387204       1 wrap.go:42] GET /api/v1/namespaces/kube-system/endpoints/kube-scheduler: (3.514372ms) 200 [[kube-scheduler/v1.10.5 (linux/amd64) kubernetes/32ac1c9/leader-election] 127.0.0.1:46290]",
   "stream": "stdout",
   "time": "2018-10-05T21:51:21.387477546Z",
   "docker": {
      "container_id": "a442fd2982dfdc09ab6235941f8d661a0a5c8df5e1d21f23ff48a9923ac14739"
   },
   "kubernetes": {
      "container_name": "kube-apiserver",
      "namespace_name": "kube-system",
      "pod_name": "kube-apiserver-ip-172-20-122-71.us-west-2.compute.internal",
      "pod_id": "80fa5e13-c8b9-11e8-a456-0a8c1424d0d4",
      "labels": {
         "k8s-app": "kube-apiserver"
      },
      "host": "ip-172-20-122-71.us-west-2.compute.internal",
      "master_url": "https://100.64.0.1:443/api",
      "namespace_id": "9b9b75b7-aa16-11e8-9d62-06df85b5d3bc"
   }
}