Observability — Logging FAQ

Observability — Logging FAQ

This page contains some of the frequently asked questions about logging.

How to change the log store to the external Elasticsearch and shut down the internal Elasticsearch
How to change the log store to Elasticsearch with X-Pack Security enabled
How to set the data retention period of logs, events, auditing logs, and Istio logs
I cannot find logs from workloads on some nodes using Toolbox
The log search page in Toolbox gets stuck when loading
Toolbox shows no log record today
I see Internal Server Error when viewing logs in Toolbox
How to make KubeSphere only collect logs from specified workloads

How to change the log store to the external Elasticsearch and shut down the internal Elasticsearch

If you are using the KubeSphere internal Elasticsearch and want to change it to your external alternate, follow the steps below. If you haven’t enabled the logging system, refer to KubeSphere Logging System to setup your external Elasticsearch directly.

First, you need to update the KubeKey configuration. Execute the following command:
```
kubectl edit cc -n kubesphere-system ks-installer
```

Comment out es.elasticsearchDataXXX, es.elasticsearchMasterXXX and status.logging, and set es.externalElasticsearchHost to the address of your Elasticsearch and es.externalElasticsearchPort to its port number. Below is an example for your reference.

apiVersion: installer.kubesphere.io/v1alpha1
kind: ClusterConfiguration
metadata:
  name: ks-installer
  namespace: kubesphere-system
  ...
spec:
  ...
  common:
    es:
      # elasticsearchDataReplicas: 1
      # elasticsearchDataVolumeSize: 20Gi
      # elasticsearchMasterReplicas: 1
      # elasticsearchMasterVolumeSize: 4Gi
      elkPrefix: logstash
      logMaxAge: 7
      externalElasticsearchHost: <192.168.0.2>
      externalElasticsearchPort: <9200>
  ...
status:
  ...
  # logging:
  #  enabledTime: 2020-08-10T02:05:13UTC
  #  status: enabled
  ...

Rerun ks-installer.

kubectl rollout restart deploy -n kubesphere-system ks-installer

Remove the internal Elasticsearch by running the following command. Please make sure you have backed up data in the internal Elasticsearch.
```
helm uninstall -n kubesphere-logging-system elasticsearch-logging
```

Change the configuration of Jaeger if Istio is enabled.

$ kubectl -n istio-system edit jaeger 
...
 options:
      es:
        index-prefix: logstash
        server-urls: http://elasticsearch-logging-data.kubesphere-logging-system.svc:9200  # Change it to the external address.

How to change the log store to Elasticsearch with X-Pack Security enabled

Currently, KubeSphere doesn’t support the integration of Elasticsearch with X-Pack Security enabled. This feature is coming soon.

How to set the data retention period of logs, events, auditing logs, and Istio logs

Before KubeSphere 3.4, you can only set the retention period of logs, which is 7 days by default. In KubeSphere 3.4, apart from logs, you can also set the data retention period of events, auditing logs, and Istio logs.

You need to update the KubeKey configuration and rerun ks-installer.

Execute the following command:

kubectl edit cc -n kubesphere-system ks-installer

In the YAML file, if you only want to change the retention period of logs, you can directly change the default value of logMaxAge to a desired one. If you want to set the retention period of events, auditing logs, and Istio logs, you need to add parameters auditingMaxAge, eventMaxAge, and istioMaxAge and set a value for them, respectively, as shown in the following example:

apiVersion: installer.kubesphere.io/v1alpha1
kind: ClusterConfiguration
metadata:
  name: ks-installer
  namespace: kubesphere-system
  ...
spec:
  ...
  common:
    es:   # Storage backend for logging, events and auditing.
      ...
      logMaxAge: 7             # Log retention time in built-in Elasticsearch. It is 7 days by default.
      auditingMaxAge: 2
      eventMaxAge: 1
      istioMaxAge: 4
  ...

Rerun ks-installer.

kubectl rollout restart deploy -n kubesphere-system ks-installer

I cannot find logs from workloads on some nodes using Toolbox

If you deployed KubeSphere through multi-node installation and are using symbolic links for the docker root directory, make sure all nodes follow the same symbolic links. Logging agents are deployed in DaemonSets onto nodes. Any discrepancy in container log paths may cause collection failures on that node.

To find out the docker root directory path on nodes, you can run the following command. Make sure the same value applies to all nodes.

docker info -f '{{.DockerRootDir}}'

If the log search page is stuck when loading, check the storage system you are using. For example, a misconfigured NFS storage system may cause this issue.

Toolbox shows no log record today

Check if your log volume exceeds the storage limit of Elasticsearch. If so, you need to increase the Elasticsearch disk volume.

I see Internal Server Error when viewing logs in Toolbox

There can be several reasons for this issue:

Network partition
Invalid Elasticsearch host and port
The Elasticsearch health status is red

How to make KubeSphere only collect logs from specified workloads

The KubeSphere logging agent is powered by Fluent Bit. You need to update the Fluent Bit configuration to exclude certain workload logs. To modify the Fluent Bit input configuration, run the following command:

kubectl edit input -n kubesphere-logging-system tail

Update the field Input.Spec.Tail.ExcludePath. For example, set the path to /var/log/containers/*_kube*-system_*.log to exclude any log from system components.

For more information, see Fluent Operator.

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