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Nginx Ingress Log Shipping

Kubernetes is gaining popularity every day. Using an Ingress controller is the preferred method of allowing external access to the services in a cluster. This makes Ingress logs incredibly important for tracking the performance of your services, issues, bugs, and the security of your cluster.

Ship Ingress logs

Note: Make sure that the following prerequisites are met before continuing:

Enable JSON logging, by updating the Ingress config section:

defaultBackend:
  replicaCount: 2

controller:
  kind: DaemonSet
  extraEnvs:
    - name: LOGS_TOKEN
      value: "<YOUR_LOGS_TOKEN>"
  config:
    use-forwarded-headers: "true"
    use-geoip: "false"
    use-geoip2: "false"
    log-format-escape-json: "true"
    log-format-upstream: '{ 
      "@timestamp": "$time_iso8601", 
      "remote_addr": "$remote_addr",
      "x-forward-for": "$proxy_add_x_forwarded_for", 
      "request_id": "$req_id", 
      "remote_user": "$remote_user", 
      "bytes_sent": $bytes_sent, 
      "request_time": $request_time, 
      "status": $status, 
      "vhost": "$host", 
      "request_proto": "$server_protocol", 
      "path": "$uri", 
      "request_query": "$args", 
      "request_length": $request_length, 
      "duration": $request_time,
      "method": "$request_method", 
      "http_referrer": "$http_referer", 
      "http_user_agent": "$http_user_agent" 
    }'

To limit log collection to the default and ingress namespaces, use the MATCH_BY_NAME option.

Create an agent.yaml file that looks like this:

region: US
logsToken: "<YOUR_LOGS_TOKEN>"
logagent:
  config:
    MATCH_BY_NAME: .*_(default|ingress)_.*

Setup Logagent to parse and ship logs:

helm install --name agent stable/sematext-agent -f agent.yaml

Remove log enrichment

Some of the larger fields like container, labels and logSource are added by Logagent for better context. These can be removed by using the REMOVE_FIELDS option in Logagent:

Add the REMOVE_FIELDS option to your agent.yaml:

region: US
logsToken: "<YOUR_LOGS_TOKEN>"
logagent:
  config:
    MATCH_BY_NAME: .*_(default|ingress)_.*
    REMOVE_FIELDS: container,labels,logSource

Run the Helm upgrade command:

helm upgrade agent stable/sematext-agent -f agent.yaml

Remove unneeded fields

The same thing can be done by removing the unneeded fields from the Nginx Ingress log format.

log-format-upstream: '{ 
  "@timestamp": "$time_iso8601", 
  "remote_addr": "$remote_addr",
  "bytes_sent": $bytes_sent, 
  "request_time": $request_time, 
  "status": $status, 
  "vhost": "$host", 
  "request_proto": "$server_protocol", 
  "path": "$uri", 
  "request_query": "$args", 
  "request_length": $request_length, 
  "duration": $request_time, 
  "method": "$request_method", 
  "http_user_agent": "$http_user_agent" 
}'

Remove unneeded logs

To reduce logs size even further, some of the logs can be dropped. For example the 2xx requests can filtered by using the IGNORE_LOGS_PATTERN option in Logagent:

Add the IGNORE_LOGS_PATTERN option to your agent.yaml:

region: US
logsToken: "<YOUR_LOGS_TOKEN>"
logagent:
  config:
    MATCH_BY_NAME: .*_(default|ingress)_.*
    REMOVE_FIELDS: container,labels,logSource
    IGNORE_LOGS_PATTERN: \"status\":\s20

Run the Helm upgrade once again:

helm upgrade agent stable/sematext-agent -f agent.yaml

By using MATCH_BY_NAME you can limit log collection to desired namespaces. Unneeded fields can be removed using REMOVE_FIELDS in the configuration. Even entire log lines can be ignored with IGNORE_LOGS_PATTERN. Logagent makes it easy to slim down any logs with very little effort.