Troubleshooting

Shamelessly stolen from https://karlkfi.medium.com/devops-troubleshooting-df937724c6cf

But it needs more IMHO.

Original author: Karl Isenberg

Title: DevOps Troubleshooting'

Jul 1, 2020·3 min read

My Preamble

Keep a log of you activity, a journal. Even if the org you are with doesn't have a formal process you should have a note pad up where you can record timestamps of activities, ideas, yours and other's. Capture outputs. and keep a record of things you tried. and or changes that were made. and other bits of information you collect. For example : "the log showed no commits in the last 4 hours". "front end traffic patterns were not unusual"

The notes will come in handy 10 minutes later when you've ruled out the first three ideas and you can't remember what Joe said at the beginning of the call, ( nor can Joe :P )

This can also help late comers to the issue get up to speed.

Start

Many technical people “just know” how to troubleshoot a technical issue, from experience, example, or trial and error, but many of those same highly technical people, when put on the spot, can’t necessarily tell you HOW they troubleshoot.

How do YOU troubleshoot?

Basic Troubleshooting Framework

The obvious answer is, “It depends,” but that’s not very satisfying, unless you can give a host of classes of problems and how to deal with them. Instead, lets look at some high level steps that describe how you might approach any technical problem.

Identify the symptoms

• error rates?
• latency?
• increased resource consumption: CPU , RAM IO
• service up / down ?
• wrong request/response data?
• too big/small request/response data?

1. Gather and examine detailed information
2. Hypothesize potential causes
3. Verify hypotheses one by one, in order of most likely and/or simplest to fix
4. Devise a plan to solve the problem
5. Implement the solution plan
6. Verify the issue was resolved
7. Repeat as needed

Incident Management Objectives

The above steps apply to almost any issue, but what if you’re on-call for a production system? Generally production readiness includes having an incident management process which can be trained and followed to ensure the following goals are met:

• Resolve an incident as quickly as possible (small MTTR)

This might be

• Ensure client satisfaction with support quality

This boils down to communicating early, clearly, concisely, truthfully, and often.

• Keep clients and stakeholders up to date on what to expect so they can plan accordingly

This boils down to communicating early, clearly, concisely, truthfully, and often.

• Follow up with analysis and action items to avoid this issue in the future

This might be

Incident Management Framework

One nice thing about a DevOps culture is that the people who are on-call for the production systems are also developers. Having a developer on-call can shorten the resolution time of an incident and sometimes provide a better, more knowledgeable and informed solution, because they have more in-depth domain knowledge of the system. Because of this, the process for incident management might look a little different, with less scripted run books to follow, and more in-depth, iterative troubleshooting.

The following steps describe one way you can combine the Basic Troubleshooting Framework with additional process to meet the Incident Management Objectives.

• Identify the symptoms, scope, impact, and urgency

• Raise the alarm and ask for help

• Gather and examine detailed information (logs, metrics, errors, traces, current state)

• Assign a communications lead (to allow the problem solvers to focus) & communicate status regularly

• Establish a war room and/or video conference, if the severity merits it

• Hypothesize potential causes

• Try to reproduce & record the steps

• Verify hypotheses one by one (or in parallel, if in a group) in order of most likely and/or simplest to fix

Stem the bleeding quickly, if possible.

For example you might want to scale up a deployment right away to give yourself some headroom. This might be dangerous if it consumes resources that choke other system, so do this with care.

Brainstorm more hypotheses, if needed

I call the process Scatter/gather. When coming up with ideas, they may scatter all over the place. When you need to act first you must "gather" and decide which idea to execute on first. Sometimes ideas come in faster than you can properly evaluate them. Prioritizing ideas is important. Are some ideas easy to rule out? Are some ideas "intractable"? You might need to hold on to an idea and revisit it 10 minutes later, don't loose those ideas. Take notes.

Identify the chain of causality (root causes)

This is often tightly linked with generating hypotheses.

Closely monitor the behaviour

... after a fix has been applied to quickly detect if the problem resurfaces or side effects occur.

Postmortem

• Have a postmortem to share the knowledge and identify improvements to product and process

Admit mistake

• Admit mistakes and be honest, but avoid blame, shame, or punishment

Reward overtime

• Reward overtime so that being on-call isn’t just a chore

Praise participants

• Praise participants who played their part well, not just the one who discovered or solved the issue

Not Perfect, But Good Enough

No process is perfect, of course. This one was assembled from years of experience both problem solving and being on-call, but you may have more experience yourself. So feel free to adopt the above steps and modify as needed. If I missed something important or you think they’re out of order, feel free to drop me a note in the comments. I’ll be using this as a reference too, so I may update it as needed.

Cloud Guy. Anthos Solutions Architect at Google (opinions my own). X-Cruise, X-Mesosphere, & X-Pivotal.

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