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Version: v2.5

Outputs and ClusterOutputs

See the Logging operator documentation for the full details on how to configure Flows and ClusterFlows.

See Rancher Integration with Logging Services: Troubleshooting for how to resolve memory problems with the logging buffer.

Outputs​

As of Rancher v2.5.8, the Outputs and ClusterOutputs can now be configured by filling out forms in the Rancher UI.

The Output resource defines where your Flows can send the log messages. Outputs are the final stage for a logging Flow.

The Output is a namespaced resource, which means only a Flow within the same namespace can access it.

You can use secrets in these definitions, but they must also be in the same namespace.

For the details of Output custom resource, see OutputSpec..

The Rancher UI provides forms for configuring the following Output types:

  • Amazon ElasticSearch
  • Azure Storage
  • Cloudwatch
  • Datadog
  • Elasticsearch
  • File
  • Fluentd
  • GCS
  • Kafka
  • Kinesis Stream
  • LogDNA
  • LogZ
  • Loki
  • New Relic
  • Splunk
  • SumoLogic
  • Syslog

The Rancher UI provides forms for configuring the Output type, target, and access credentials if applicable.

For example configuration for each logging plugin supported by the logging operator, see the Logging operator documentation.

ClusterOutputs​

ClusterOutput defines an Output without namespace restrictions. It is only effective when deployed in the same namespace as the logging operator.

For the details of the ClusterOutput custom resource, see ClusterOutput.

YAML Examples​

Once logging is installed, you can use these examples to help craft your own logging pipeline.

Cluster Output to ElasticSearch​

Let's say you wanted to send all logs in your cluster to an elasticsearch cluster. First, we create a cluster Output.

apiVersion: logging.banzaicloud.io/v1beta1
kind: ClusterOutput
metadata:
  name: "example-es"
  namespace: "cattle-logging-system"
spec:
  elasticsearch:
    host: elasticsearch.example.com
    port: 9200
    scheme: http

We have created this ClusterOutput, without elasticsearch configuration, in the same namespace as our operator: cattle-logging-system.. Any time we create a ClusterFlow or ClusterOutput, we have to put it in the cattle-logging-system namespace.

Now that we have configured where we want the logs to go, let's configure all logs to go to that ClusterOutput.

apiVersion: logging.banzaicloud.io/v1beta1
kind: ClusterFlow
metadata:
  name: "all-logs"
  namespace: "cattle-logging-system"
spec:
  globalOutputRefs:
    - "example-es"

We should now see our configured index with logs in it.

Output to Splunk​

What if we have an application team who only wants logs from a specific namespaces sent to a splunk server? For this case, we can use namespaced Outputs and Flows.

Before we start, let's set up that team's application: coolapp.

apiVersion: v1
kind: Namespace
metadata:
  name: devteam
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: coolapp
  namespace: devteam
  labels:
    app: coolapp
spec:
  replicas: 2
  selector:
    matchLabels:
      app: coolapp
  template:
    metadata:
      labels:
        app: coolapp
    spec:
      containers:
        - name: generator
          image: paynejacob/loggenerator:latest

With coolapp running, we will follow a similar path as when we created a ClusterOutput. However, unlike ClusterOutputs, we create our Output in our application's namespace.

apiVersion: logging.banzaicloud.io/v1beta1
kind: Output
metadata:
  name: "devteam-splunk"
  namespace: "devteam"
spec:
  splunkHec:
    hec_host: splunk.example.com
    hec_port: 8088
    protocol: http

Once again, let's feed our Output some logs:

apiVersion: logging.banzaicloud.io/v1beta1
kind: Flow
metadata:
  name: "devteam-logs"
  namespace: "devteam"
spec:
  localOutputRefs:
    - "devteam-splunk"

Output to Syslog​

Let's say you wanted to send all logs in your cluster to an syslog server. First, we create a ClusterOutput:

apiVersion: logging.banzaicloud.io/v1beta1
kind: ClusterOutput
metadata:
  name: "example-syslog"
  namespace: "cattle-logging-system"
spec:
  syslog:
    buffer:
      timekey: 30s
      timekey_use_utc: true
      timekey_wait: 10s
      flush_interval: 5s
    format:
      type: json
      app_name_field: test
    host: syslog.example.com
    insecure: true
    port: 514
    transport: tcp

Now that we have configured where we want the logs to go, let's configure all logs to go to that Output.

apiVersion: logging.banzaicloud.io/v1beta1
kind: ClusterFlow
metadata:
  name: "all-logs"
  namespace: cattle-logging-system
spec:
  globalOutputRefs:
    - "example-syslog"

Unsupported Outputs​

For the final example, we create an Output to write logs to a destination that is not supported out of the box:

Note on syslog As of Rancher v2.5.4, syslog is a supported Output. However, this example still provides an overview on using unsupported plugins.

apiVersion: v1
kind: Secret
metadata:
  name: syslog-config
  namespace: cattle-logging-system
type: Opaque
stringData:
  fluent-bit.conf: |
    [INPUT]
        Name              forward
        Port              24224

    [OUTPUT]
        Name              syslog
        InstanceName      syslog-output
        Match             *
        Addr              syslog.example.com
        Port              514
        Cluster           ranchers

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: fluentbit-syslog-forwarder
  namespace: cattle-logging-system
  labels:
    output: syslog
spec:
  selector:
    matchLabels:
      output: syslog
  template:
    metadata:
      labels:
        output: syslog
    spec:
      containers:
      - name: fluentbit
        image: paynejacob/fluent-bit-out-syslog:latest
        ports:
          - containerPort: 24224
        volumeMounts:
          - mountPath: "/fluent-bit/etc/"
            name: configuration
      volumes:
      - name: configuration
        secret:
          secretName: syslog-config
---
apiVersion: v1
kind: Service
metadata:
  name: syslog-forwarder
  namespace: cattle-logging-system
spec:
  selector:
    output: syslog
  ports:
    - protocol: TCP
      port: 24224
      targetPort: 24224
---
apiVersion: logging.banzaicloud.io/v1beta1
kind: ClusterFlow
metadata:
  name: all-logs
  namespace: cattle-logging-system
spec:
  globalOutputRefs:
    - syslog
---
apiVersion: logging.banzaicloud.io/v1beta1
kind: ClusterOutput
metadata:
  name: syslog
  namespace: cattle-logging-system
spec:
  forward:
    servers:
      - host: "syslog-forwarder.cattle-logging-system"
    require_ack_response: false
    ignore_network_errors_at_startup: false

Let's break down what is happening here. First, we create a deployment of a container that has the additional syslog plugin and accepts logs forwarded from another fluentd. Next we create an Output configured as a forwarder to our deployment. The deployment fluentd will then forward all logs to the configured syslog destination.