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5.2.2.2 Send OKE logs by FluentD

Use OpenSearch and OpenSearch Dashboard instead of ElasticSearch and Kibana in your EFK configuration.

Fluentd configuration

1. Create a Service Account for Fluentd installation and define the relevant permissions.

2. configmap to define additional settings

   • Fluentd-related settings are all defined in a .conf file under /fluentd/etc/ in the container. You can override these files.
   • OCI OpenSearch clusters now use Self Signed certificates by default. Leave only the basics that are absolutely necessary for the connection. If you leave the commented out part and don’t set a value, you will get an error at run time.

3. Define a fluentd damonset

   • Some changes have been made to the YAML in the Fluentd documentation to use the configured configmap.
   • We are changing to use fluent.conf overridden by configmap.
   • You are setting up the Self Signed CA used by the OpenSearch Dashboard.

Install FluentD

1. In fluentd-daemonset-opensearch.yaml, change FLUENT_OPENSEARCH_HOST to the target OpenSearch host.

   ...
           env:
             - name:  FLUENT_OPENSEARCH_HOST
               value: "amaaaaaavsea7yia3enl6q6yrwekrd7qpi3yqaphhcvwowtmzftkt45jel7a.opendashboard.ap-chuncheon-1.oci.oraclecloud.com"
             - name:  FLUENT_OPENSEARCH_PORT
               value: "9200"
             ...
   

2. Install FluentD

   kubectl apply -f fluentd-rbac.yaml
   kubectl apply -f fluentd-configmap-opensearch.yaml
   kubectl apply -f fluentd-daemonset-opensearch.yaml
   

3. Add a security rule to send logs from OKE cluster Worker Node to OpenSearch.

   • Worker Node security rules

     • Target: ex) oke-nodeseclist-quick-oke-cluster-1-04cdcc334

     • Egress Rules:

       The example below is when the OpenSearch location is subnet 10.0.20.0/24.

       Stateless	Destination	IP Protocol	Source Port Range	Destination Port Range	Description
       No	10.0.20.0/24	TCP	All	9200	OpenSearch API

   • Security rules of OpenSearch

     • Target: ex) oke-svclbseclist-quick-oke-cluster-1-04cdcc334

     • Ingress Rules:

       In the example below, if the Worker Node is in the subnet 10.0.10.0/24,

     Stateless	Source	IP Protocol	Source Port Range	Destination Port Range	Description
     No	10.0.10.0/24	TCP	All	9200	OpenSearch API

4. Check the log

   When the fluentd Pod starts up, check the logs to see if it operates normally without any connection errors with OpenSearch.

   $ kubectl get pod -n kube-system
   NAME                                   READY   STATUS    RESTARTS      AGE
   ...
   fluentd-7hbht                          1/1     Running   0             99s
   fluentd-qwrg4                          1/1     Running   0             99s
   fluentd-zfgfz                          1/1     Running   0             99s
   ...
   $ kubectl logs -f fluentd-7hbht -n kube-system -f
   2022-10-13 15:31:30 +0000 [info]: parsing config file is succeeded path="/fluentd/etc/fluent.conf"
   ...
   2022-10-13 15:31:32 +0000 [info]: adding match pattern="**" type="opensearch"
   ...
   2022-10-13 15:31:32 +0000 [info]: #0 starting fluentd worker pid=14 ppid=6 worker=0
   2022-10-13 15:31:32 +0000 [info]: #0 [in_tail_container_logs] following tail of /var/log/containers/proxymux-client-s75ds_kube-system_proxymux-client-eca8e5e37a2dbf317be4f25cddcce1f4659c5bf9adecccdf522f1f2317b17dc3.log
   2022-10-13 15:31:32 +0000 [info]: #0 [in_tail_container_logs] following tail of /var/log/containers/csi-oci-node-vlgnm_kube-system_csi-node-driver-d566fd830f5a575b4d3724946f4a09a23bdf7615527b511a42cbae57c27bab0d.log
   

OpenSearch Dashboard Settings

1. If you have not connected to the jumpbox VM through SSH tunneling, reconnect.

2. Since SSH tunneling is done, check the connection to the OpenSearch Dashboard with a browser locally.

   • Access address: https://localhost:5601

3. In the upper left navigation menu, click OpenSearch Dashboards > Discover.

   

4. Click Create index pattern.

5. Create an index pattern.

   Among the three sources shown below, we use the fluentd source.

   • Index pattern name: fluentd
   • Time field: time

   

   

6. You can see the result of adding the index pattern.

   

7. Click OpenSearch Dashboards > Discover in the upper left navigation menu.

8. You can check the collected logs through the created index pattern.

   • To check the log of the test app, click Add filter to specify namespace_name=default .

   

9. Access the test app.

   • Ex) http://129.154.xxx.xxx/?opensearch-test

10. Check the log

    You can check the log of the test app in the OpenSearch Dashboard as shown below.