Centralized Logging Patterns
A presentation at DEVOPS.BARCELONA in in Barcelona, Spain by Philipp Krenn
Centralized Logging Patterns Philipp Krenn @xeraa @xeraa
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Developer @xeraa
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Disclaimer I build highly monitored Hello World apps @xeraa
Example: Java SLF4J, Logback, MDC with logstash-logback-encoder Alternative https://github.com/vy/log4j2-logstash-layout @xeraa
And Everywhere Else .NET: NLog JavaScript: Winston Python: structlog PHP: Monolog @xeraa
Anti-Pattern: print System.out.println(“Oops”); @xeraa
Anti-Pattern: Coupling @xeraa
Parse @xeraa
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Bind Mount Logs java_app: volumes: - ‘./logs-docker/:/logs/’ … filebeat_for_logstash: volumes: - ‘./logs-docker/:/mnt/logs/:ro’ … @xeraa
Collect Log Lines filebeat.inputs: - type: log paths: - /mnt/logs/*.log @xeraa
Metadata processors: - add_host_metadata: ~ @xeraa
Test Multiline Pattern https://www.elastic.co/guide/ en/beats/filebeat/current/ test_your_regexp_pattern_for multiline.html @xeraa
Grok https://github.com/logstashplugins/logstash-patternscore/blob/master/patterns/ grok-patterns @xeraa
Dev Tools Grok Debugger @xeraa
[2018-09-28 10:30:38.516] ERROR net.xeraa.logging.LogMe [main] user_experience= , session=46, loop=15 Wake me up at night java.lang.RuntimeException: Bad runtime… at net.xeraa.logging.LogMe.main(LogMe.java:30) ^[%{TIMESTAMP_ISO8601:@timestamp}]%{SPACE}%{LOGLEVEL:log.level} %{SPACE}%{USERNAME:log.package}%{SPACE}[%{WORD:log.method}] %{SPACE}-%{SPACE}%{GREEDYDATA:log.labels}%{SPACE}-%{SPACE} %{GREEDYDATA:message}(?:\n+(?<stacktrace>(?:.|\r|\n)+))? @xeraa
Machine Learning Data Visualizer @xeraa
Logstash Key Value Filter for MDC kv { source => “labels” field_split => “,” trim_key => ” ” } @xeraa
Pro: No change Con: Regular expression, multiline, format changes @xeraa
Send @xeraa
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logback.xml <appender name=”logstash” class=”net.logstash.logback.appender.LogstashAccessTcpSocketAppender”> <destination>logstash:4560</destination> <encoder class=”net.logstash.logback.encoder.LogstashEncoder”/> </appender> @xeraa
Pro: No files Con: Outages & coupling @xeraa
Structure @xeraa
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Collect JSON filebeat.input: - type: log paths: - /mnt/logs/*.json json: message_key: message keys_under_root: true @xeraa
Stack(trace) Hash @xeraa
Bonues: Multi-Index output.elasticsearch: hosts: [“http://localhost:9200”] indices: - index: “warning-%{[agent.version]}-%{+yyyy.MM.dd}” when.contains: message: “WARN” - index: “error-%{[agent.version]}-%{+yyyy.MM.dd}” when.contains: message: “ERR” @xeraa
Pro: Right format Con: JSON serialization overhead @xeraa
Containerize @xeraa
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Where to put Filebeat? Sidecar @xeraa
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https://github.com/elastic/beats/tree/ master/deploy/docker @xeraa
Docker Logs filebeat.autodiscover: providers: - type: docker hints.enabled: true processors: - add_docker_metadata: ~ @xeraa
Metadata No Docker metadata with the other methods @xeraa
“docker”: { “container”: { “labels”: { “app”: “fizzbuzz”, “co_elastic_logs/multiline_match”: “after”, “com_docker_compose_config-hash”: “41520c6cf2b6a1f3dae4f16d0a6fd76760cdfc38fbfe43a3a3be2e09bdd1b8b5”, “environment”: “production”, “co_elastic_logs/multiline_pattern”: “^\[“, “co_elastic_logs/multiline_negate”: “true”, “com_docker_compose_oneoff”: “False”, “com_docker_compose_project”: “java-logging”, “com_docker_compose_service”: “java_app”, “com_docker_compose_container-number”: “1”, “com_docker_compose_version”: “1.23.2” } } } @xeraa
Missing the Last Line Waiting for the newline @xeraa
Hints labels: - “app=fizzbuzz” - “co.elastic.logs/multiline.pattern=^\[” - “co.elastic.logs/multiline.negate=true” - “co.elastic.logs/multiline.match=after” @xeraa
Registry File filebeat.registry.path: /usr/share/filebeat/data/registry @xeraa
Ingest Pipeline output.elasticsearch: hosts: [“http://elasticsearch:9200”] index: “docker” pipelines: - pipeline: “parse_java” when.contains: container.name: “java_app” @xeraa
Ingest Pipeline { “description” : “Parse Java log lines”, “processors”: [ { “grok”: { “field”: “message”, “patterns”: [ “^\[%{TIMESTAMP_ISO8601:timestamp}\]%{SPACE}%{LOGLEVEL:log.level} %{SPACE}%{USERNAME:log.package}%{SPACE}\[%{WORD:log.method}\]%{SPACE}%{SPACE}%{GREEDYDATA:labels}%{SPACE}-%{SPACE}%{GREEDYDATA:message_parsed} (?:\n+(?<stacktrace>(?:.|\r|\n)+))?” ], “ignore_failure”: true } } ] } @xeraa
Unknown Fields @xeraa
ASCII Art ..-__ ''-._ _.-.. ”-._ .-.-```. ```\/ _.,_ ''-._ ( ' , .-` | `, ) |`-._`-...-` __...-.-.|’_.-'| |-.._ / _.-' |-._ -._-./ .-’ .-’ |-._-.-.__.-' _.-'_.-'| |-.-._ _.-'_.-' |-._ -._-..-‘.-’ .-’ |-._-.-.__.-' _.-'_.-'| |-.-._ _.-'_.-' |-._ -._-..-‘_.-’ _.-’ -._-..-’ _.-’ -._ _.-'-..-’
Redis 4.0.9 (00000000/0) 64 bit Running in stand alone mode Port: 6379 PID: 55757
http://redis.io
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Configuration Templates filebeat.autodiscover: providers: - type: docker templates: - condition: equals: docker.container.image: redis config: - type: docker containers.ids: - “${data.docker.container.id}” exclude_lines: [“^\s+[-`(‘.|_]”] @xeraa
Who Logs the Logger Avoid loops Process without -e filebeat.yml: logging.to_files: true @xeraa
Pro: Hot Con: Complexity @xeraa
Orchestrate @xeraa
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Where to put Filebeat? DaemonSet @xeraa
https://github.com/elastic/beats/tree/ master/deploy/kubernetes @xeraa
Metadata Either in cluster or outside processors: - add_kubernetes_metadata: in_cluster: true - add_kubernetes_metadata: in_cluster: false host: <hostname> kube_config: ${HOME}/.kube/config @xeraa
{ “host”: “172.17.0.21”, “port”: 9090, “kubernetes”: { “container”: { “id”: “382184ecdb385cfd5d1f1a65f78911054c8511ae009635300ac28b4fc357ce51”, “image”: “my-java:1.0.0”, “name”: “my-java” }, “labels”: { “app”: “java”, }, “namespace”: “default”, “node”: { “name”: “minikube” }, “pod”: { “name”: “java-2657348378-k1pnh” } }, } @xeraa
More Metadata Add: Cloud, local timezone, process Drop: Events, fields Rename: Fields Dissect, DNS reverse lookup @xeraa
Configuration Templates filebeat.autodiscover: providers: - type: kubernetes templates: - condition: equals: kubernetes.namespace: redis config: - type: docker containers.ids: - “${data.kubernetes.container.id}” exclude_lines: [“^\s+[-`(‘.|_]”] @xeraa
Customize Indices output.elasticsearch: index: “%{[kubernetes.namespace]:filebeat}-%{[beat.version]}-%{+yyyy.MM.dd}” @xeraa
Pro: Hot Con: Complexity++ @xeraa
Conclusion @xeraa
Examples https://github.com/xeraa/java-logging @xeraa
Parse Send Structure Containerize Orchestrate @xeraa
Questions? Philipp Krenn @xeraa @xeraa
Most organizations feel the need to centralize their logs — once you have more than a couple of servers or containers, SSH and tail will not serve you well any more. However, the common question or struggle is how to achieve that.
This talk presents multiple approaches and patterns with their advantages and disadvantages, so you can pick the one that fits your organization best:
- Parse: Take the log files of your applications and extract the relevant pieces of information.
- Send: Add a log appender to send out your events directly without persisting them to a log file.
- Structure: Write your events in a structured file, which you can then centralize.
- Containerize: Keep track of short lived containers and configure their logging correctly.
- Orchestrate: Stay on top of your logs even when services are short lived and dynamically allocated on Kubernetes.
Each pattern has its own demo with the open source Elastic Stack (previously called ELK Stack), so you can easily try out the different approaches in your environment. Though the general patterns are applicable with any centralized logging system.
Video
Resources
The following resources were mentioned during the presentation or are useful additional information.
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GitHub Demo Code
How to log from a Java application to the Elastic Stack.
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