Remoting Monitoring with OpenTelemetry - Coding Phase 1

Published on 2021-07-31 by Akihiro Kiuchi

Remoting Monitoring with OpenTelemetry

Goal

Goal of Remoting Monitoring with OpenTelemetry

The goal of this project:

  • collect telemetry data(metrics, traces, logs) of remoting module with OpenTelemetry.

  • send the telemetry data to OpenTelemetry Protocol endpoint

Which OpenTelemetry endpoint to use and how to visualize the data are up to users.

OpenTelemetry

OpenTelemetry Logo

An observability framework for cloud-native software

OpenTelemetry is a collection of tools, APIs, and SDKs. You can use it to instrument, generate, collect, and export telemetry data(metrics, logs, and traces) for analysis in order to understand your software’s performance and behavior.

Phase 1 summary

User survey

Our team conducted a user survey to understand the pain point regarding Jenkins remoting.

Fig 1. What agent type/plugins do you use?

End user survey result

Fig 1 shows what types of agent users use, and 17 unique respondents out of 28 use docker for agent. So I’m planning to publish a docker image to demonstrate how we can build Docker image with our monitoring feature.

This survey and investigation of JIRA tickets of past two years also tell me five common causes of agent unavailability.

  • Configuration mistakes

    • Jenkins agent settings, e.g. misuse of "tunnel connection through" option.

    • Platform settings, e.g. invalid port setting of Kubernetes' helm template.

    • Network settings, e.g. Load balancer misconfiguration.

  • Uncontrolled shutdown of nodes for downscaling.

  • Timeout during provisioning a new node.

  • Firewall, antivirus software or other network component kill the connection

  • Lack of hardware resources, e.g. memory, temp space, etc…​

We also heard valuable user voice in the survey.

What areas would you like to see better in Jenkins monitoring?

I have created a bunch of adhoc monitoring jobs to check on the agent’s health and send e-mail. Would be nice to have this consolidated.

Having archive of nodes with the access to their logs/events would have been nice.

I hope that implementing these feature with OpenTelemetry, which is expected to become the industry standard for observability, will bring great monitoring experience to Jenkins community.

Proof of Concept

How to deliver the monitoring program to agents

1. Sending monitoring program to the agent over remoting

Sending monitoring program via remoting

In my first implementation, I prepared a Jenkins plugin and send the monitoring program from Jenkins controller. However, this approach have following disadvantages.

  1. We cannot collect telemetry data before the initial connection. We are likely to encounter a problem while provisioning a new node, so it’s important to observe agents' telemetry data from the beginning.

  2. Some agent restarters (e.g. UnixSlaveRestarter) restart agent completely when reconnecting. It means that the agent lost monitoring program every time the connection closed, and we cannot collect telemetry data after the connection is lost before a new connection is established.

So we decided to take the next approach.

2. Install monitoring engine when provisioning a new agent

Installing monitoring engine when provisioning

In this approach, user will download the monitoring program called monitoring engine, which is a JAR file, and place it in the agent node when provisioning.

How to instrument remoting to produce remoting trace

Add instrumentation extension point to remoting

Pull Request: https://github.com/jenkinsci/remoting/pull/471

This approach makes the agent launch command more complicated, and we have to overcome this problem.

Current State

Metrics

We currently support the following metrics and planning to support more.

metrics

unit

label

key

description

system.cpu.load

1

System CPU load. See com.sun.management.OperatingSystemMXBean.getSystemCpuLoad

system.cpu.load.average.1m

System CPU load average 1 minute See java.lang.management.OperatingSystemMXBean.getSystemLoadAverage

system.memory.usage

bytes

state

used, free

see com.sun.management.OperatingSystemMXBean.getTotalPhysicalMemorySize and com.sun.management.OperatingSystemMXBean.getFreePhysicalMemorySize

system.memory.utilization

1

System memory utilization, see com.sun.management.OperatingSystemMXBean.getTotalPhysicalMemorySize and com.sun.management.OperatingSystemMXBean.getFreePhysicalMemorySize. Report 0% if no physical memory is discovered by the JVM.

system.paging.usage

bytes

state

used, free

see com.sun.management.OperatingSystemMXBean.getFreeSwapSpaceSize and com.sun.management.OperatingSystemMXBean.getTotalSwapSpaceSize.

system.paging.utilization

1

see com.sun.management.OperatingSystemMXBean.getFreeSwapSpaceSize and com.sun.management.OperatingSystemMXBean.getTotalSwapSpaceSize. Report 0% if no swap memory is discovered by the JVM.

process.cpu.load

%

Process CPU load. See com.sun.management.OperatingSystemMXBean.getProcessCpuLoad.

process.cpu.time

ns

Process CPU time. See com.sun.management.OperatingSystemMXBean.getProcessCpuTime.

runtime.jvm.memory.area

bytes

type

used, committed, max

see MemoryUsage

area

heap, non_heap

runtime.jvm.memory.pool

bytes

type

used, committed, max

see MemoryUsage

pool

PS Eden Space, G1 Old Gen…​

runtime.jvm.gc.time

ms

gc

G1 Young Generation, G1 Old Generation, …​

see GarbageCollectorMXBean

runtime.jvm.gc.count

1

gc

G1 Young Generation, G1 Old Generation, …​

see GarbageCollectorMXBean

Traces

We tried several approaches to instrument remoting module, but good approach is not established yet.

Here is a draft documentation of the spans to collect. Google Doc

Logs

Coming soon!

Metric and span demo visualization

Our team created a demo example with Docker compose and visualized the metrics and spans.

Click to open in new tab

prometheus metric visualization jaeger span visualization

Google Summer of Code Midterm Demo

Our project demo starts with 8:20

Next Step

  • Log support

  • Alpha release!

About the Authors
Akihiro Kiuchi

GSoC 2021 student (Jenkins Remoting Monitoring). Akihiro is a student in the Department of information and communication engineering at the University of Tokyo.