Initialize docs for functionbeat

[dedemorton]

Initial commit with docs for functionbeat. This is a work in progress (not ready to merge).

Todo after merging:

• Add an FAQ topic that explains that you need to deploy functionbeat in the same region where the services (cloud watch logs/sqs) you're monitoring are deployed.
• Should we say anything about checking for problems in the logs for the function, or is that stating the obvious?
• Remove the following topics because they are not relevant to functionbeat:
  • Set up project paths: Nothing can be really change in provider container.
  • HTTP Endpoint: This will not be accessible
  • FAQ topics that aren't relevant:
    • Logstash connection doesn’t work?
    • Need to limit bandwidth used by Functionbeat?
    • @metadata is missing in Logstash? SSL client fails to connect to Logstash?
  • The following sections under security because they are not relevant to functionbeat:
    • Secure communication with Logstash by using SSL
    • Use Linux Secure Computing Mode (seccomp)
  • Topic about Repositories for APT and YUM
• Change logging topic to indicate where that the logs are only available in the cloudwatch log group of the functionbeat lambda. Maybe mention AWS panel.

[ph]

@dedemorton I did a first pass on this PR, ping me for any followup.

[dedemorton]

@ph I've made most of your changes (and marked them as resolved), but I won't push the updates until I've tested and made more updates. I have a couple of follow up questions in the mean time.

[dedemorton]

@ph Pushed some changes. This is ready for another review.

[dedemorton]

@ph I've resolved all the issues you identified. I still need to hear back about the download path. I've uploaded the files to firebase if you want to see the rendered docs without having to build them: https://functionbeat-ad51b.firebaseapp.com/

[ph]

@dedemorton It is possible to remove the Repositories for APT and YUM in the getting started section of functionbeat?

[ph]

@dedemorton Yeah the docs are beta, I think the main problem is to remove stuff that doesn't apply to functionbeat :(

• I found a Keystore issue at Functionbeat: Keystore file is missing when we deploy the beat on the serverless env. #9009
• I see 2 kibana screen shot in the PR, where they are used?
• I would remove section about Set up project paths: Nothing can be really change in provider container.
• Remove section HTTP Endpoint: This will not be accessible

Can we filter out some items from the FAQ https://functionbeat-ad51b.firebaseapp.com/faq.html?
I think the items below are not really related to functionbeat.

• Logstash connection doesn’t work?
• Need to limit bandwidth used by Functionbeat?
• @metadata is missing in Logstash?
• SSL client fails to connect to Logstash?

The logging section, we will need to adjust that, all the selectors are valid, the log level is valid, changing where the log need to be is invalid, since the log are only available in the cloudwatch log group of the functionbeat lambda.

[ph]

Can we add the options from https://github.com/elastic/beats/blob/master/x-pack/functionbeat/functionbeat.reference.yml

    # Concurrency, is the reserved number of instances for that function.
    # Default is unreserved.
    #
    # Note: There is a hard limit of 1000 functions of any kind per account.
    #concurrency: 5

    # The maximum memory allocated for this function, the configured size must be a factor of 64.
    # There is a hard limit of 3008MiB for each function. Default is 128MiB.
    #memory_size: 128MiB

    # Dead letter queue configuration, this must be set to an ARN pointing to a SQS queue.
#dead_letter_config.target_arn:

Concurrency is the most important, this is the option to control your cost, by default in the initial release we run in an unreserved way, but 6.5.1 we will use a default of 5.