alphagov / paas-syslog-release

Syslog BOSH Release

• Slack: #syslog on https://slack.cloudfoundry.org
• Tracker: CF Platform Logging Improvements
• CI: Syslog CI

1. Usage
2. Configureation
3. Custom Rules
4. Output Format
5. Tech Notes
6. Development

This is a BOSH release to forward local syslog events in RFC5424 format to a remote syslog endpoint. It currently uses RSYSLOG which is pre-installed by the stemcell.

Usage

Download the latest release from bosh.io and include it in your manifest:

releases:
- name: syslog
  version: latest

If you are deploying the Cloud Foundry Application Runtime using cf-deployment, there is an ops-file available that will add the syslog release and syslog_forwarder job, and expose configuration variables.

Otherwise, you can co-locate and configure the syslog_forwarder yourself.

Configure Forwarding

Add the syslog_forwarder to forward all local syslog messages from an instance to a syslog endpoint. Configure address and, optionally, port and transport:

instance_groups:
- name: some-instance-group
  jobs:
  - name: syslog_forwarder
    release: syslog
  properties:
    syslog:
      address: <IP or hostname>

By default, if the syslog endpoint is unavailable, messages will be queued. Alternatively, configure fallback_servers for higher availability. Only TCP or RELP are supported for fallback functionality:

properties:
  syslog:
    address: 10.10.10.100
    fallback_servers:
    - address: 10.10.10.101
    - address: 10.10.10.102

TLS is supported with additional properties. The following example would forward syslog messages to papertrail:

properties:
  syslog:
    address: logs4.papertrailapp.com
    port: 12345
    transport: tcp
    tls_enabled: true
    permitted_peer: "*.papertrailapp.com"
    ca_cert: |
      -----BEGIN CERTIFICATE-----
      MIIFdDCCBFygAwIBAgIQJ2buVutJ846r13Ci/ITeIjANBgkqhkiG9w0BAQwFADBv
      ...
      pu/xO28QOG8=
      -----END CERTIFICATE-----
      -----BEGIN CERTIFICATE-----
      MIIENjCCAx6gAwIBAgIBATANBgkqhkiG9w0BAQUFADBvMQswCQYDVQQGEwJTRTEU
      ...
      mnkPIAou1Z5jJh5VkpTYghdae9C8x49OhgQ=
      -----END CERTIFICATE-----

Alternatively, if the intended syslog recipient's certificate is signed by any Certificate Authority in the BOSH instances' cert store (most common CAs are included on the stemcell), you can omit the ca_cert field entirely.

If you do include ca_cert, please note that the standard cert store will no longer be referenced. This necessitates including the entire certificate chain.

Custom Rule

This release allows a custom rule to be inserted before the rule that accomplishes log forwarding. This can be useful if you only wish to forward certain logs, or if there is a certain type of log you wish to exclude from forwarding.

We have some simple documentation with a few example rules in example-custom-rules.md.

Please note: if your custom rule is invalid, it will be logged and discarded.

Test Store

The syslog_storer is meant for testing. Deploy it and configure your instances to forward logs to it. It provides a link that the forwarder consumes, so if they are deployed together and the forwarder is otherwise unconfigured, logs should be sent to the storer. It should not be co-located with other jobs which also try to configure syslog. Received logs are stored in /var/vcap/store/syslog_storer/syslog.log.

You can add it to a deployment manifest very simply:

instance_groups:
- name: syslog_storer
  jobs:
  - name: syslog_storer
    release: syslog

Remember to allow inbound traffic on TCP port 514 in your IaaS security groups.

The storer can also be used to test TLS connections. If you provide a Certificate Authority to the syslog.tls.generation properties, each storer instance will generate a cert signed by that CA at startup, with the instance's IP address as the common name. You will need to explicitly configure this CA's cert as trusted on the forwarder.

Format

This release forwards messages using the RFC5424 standard (natively supported by most log platforms). Forwarded messages are annotated with structured data that identify the originating BOSH instance (director, deployment, availability zone, instance group, and instance ID). Forwarded messages are also tagged with our private enterprise number, 47450.

<$PRI>$VERSION $TIMESTAMP $HOST $APP_NAME $PROC_ID $MSG_ID [instance@47450 director="$DIRECTOR" deployment="$DEPLOYMENT" group="$INSTANCE_GROUP" az="$AVAILABILITY_ZONE" id="$ID"] $MESSAGE

An example message from diego is transmitted as:

<14>1 2017-01-25T13:25:03.18377Z 192.0.2.10 etcd - - [instance@47450 director="test-env" deployment="cf" group="diego_database" az="us-west1-a" id="83bd66e5-3fdf-44b7-bdd6-508deae7c786"] [INFO] the leader is [https://diego-database-0.etcd.service.cf.internal:4001]
<14>1 2017-01-25T13:25:03.184491Z 192.0.2.10 bbs - - [instance@47450 director="test-env" deployment="cf" group="diego_database" az="us-west1-a" id="83bd66e5-3fdf-44b7-bdd6-508deae7c786"] {"timestamp":"1485350702.539694548","source":"bbs","message":"bbs.request.start-actual-lrp.starting","log_level":1,"data":{"actual_lrp_instance_key":{"instance_guid":"271f71c7-4119-4490-619f-4f44694717c0","cell_id":"diego_cell-2-41f21178-d619-4976-901c-325bc2d0d11d"},"actual_lrp_key":{"process_guid":"1545ce89-01e6-4b8f-9cb1-5654a3ecae10-137e7eb4-12de-457d-8e3e-1258e5a74687","index":5,"domain":"cf-apps"},"method":"POST","net_info":{"address":"192.0.2.12","ports":[{"container_port":8080,"host_port":61532},{"container_port":2222,"host_port":61533}]},"request":"/v1/actual_lrps/start","session":"418.1"}}

A sample logstash config with filters to extract instance metadata is in scripts/logstash-filters.conf.

Tech Notes

RSYSLOG is a system for log processing; it is a drop-in replacement for the UNIX's venerable syslog, which logs messages to various files and/or log hosts. RSYSLOG can be configured as a storer (i.e. it receives log messages from other hosts) or a forwarder (i.e. it forwards system log messages to RSYSLOG storers, syslog servers, or log aggregation services).

The RSYSLOG configuration file is /etc/rsyslog.conf. The RSYSLOG forwarder's customizations are rendered into /etc/rsyslog.d/rsyslog.conf, which is included by the configuration file.

Development

In order to build releases or run tests, you will need to initialize and update the blackbox submodule:

git submodule init && git submodule update

There's a suite of acceptance tests in the tests/ directory. To use them, you will need to install Go.

Before running tests, you will need to create a bosh director. First you should ensure the bosh2 cli is installed and the bosh-deployment repository is downloaded and located at ~/workspace/bosh-deployment. You can then run ./scripts/setup-bosh-lite-for-tests.sh to create the director. Afterwards execute source export-bosh-lite-creds.sh to target the bosh director.

The tests can then be run from the top of the repo with ./scripts/test.

For more details, see tests/README.md.

We are unlikely to merge PRs that add features without tests. Please submit all pull requests against the develop branch.