BOSH release for forwarding logs (either sent to syslog or picked up /var/vcap/sys/log/**/*)
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CF Syslog Bot
CF Syslog Bot Final release 11.4.0
Latest commit 1ab5ef0 Sep 26, 2018

Syslog BOSH Release

  1. Usage
  2. Configuration
  3. Custom Rules
  4. Output Format
  5. Tech Notes
  6. Development
  7. CI

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.

There is a separate release to accomplish this on Windows stemcells, which uses blackbox, but not rsyslog.


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

- 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:

- name: some-instance-group
  - name: syslog_forwarder
    release: 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:

    - address:
    - address:

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

    port: 12345
    transport: tcp
    tls_enabled: true
    permitted_peer: "*"
    ca_cert: |
      -----BEGIN CERTIFICATE-----
      -----END CERTIFICATE-----
      -----BEGIN CERTIFICATE-----
      -----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

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:

- name: syslog_storer
  - 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.


This release forwards messages using the RFC5424 standard, which is natively supported by most log platforms.

Forwarded messages are annotated with structured data. The Structured Data ID is instance@47450, which is intended to allow parsing rules specific to the structured data emitted by BOSH instances using this release. (The 47450 is our private enterprise number.) The structured data contains the following fields:

  • director
  • deployment
  • availability zone
  • instance group
  • instance ID

The whole thing looks something like this:


Here are a couple of example messages from diego:

<14>1 2017-01-25T13:25:03.18377Z etcd rs2 - [instance@47450 director="test-env" deployment="cf" group="diego_database" az="us-west1-a" id="83bd66e5-3fdf-44b7-bdd6-508deae7c786"] [INFO] the leader is []
<14>1 2017-01-25T13:25:03.184491Z bbs rs2 - [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":"","ports":[{"container_port":8080,"host_port":61532},{"container_port":2222,"host_port":61533}]},"request":"/v1/actual_lrps/start","session":"418.1"}}

Note: the rs2 PROC_ID in the above indicates that the logs have been forwarded from a file by blackbox, which uses remote_syslog2 under the covers.

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. 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 default RSYSLOG configuration file is /etc/rsyslog.conf. On the stemcell, this specifies that configuration in/etc/rsyslog.d/* will also be respected. The RSYSLOG forwarder's customizations are rendered into several files following the format /etc/rsyslog.d/[0-9][0-9]-syslog-release-*.conf.

Note: syslog-release deletes files in its pattern, and /etc/rsyslog.d/rsyslog.conf, a legacy config location, during prestart.

BLACKBOX is used for forwarding from files. It was historically an experiment by the Concourse team, but now it's just used to forward logs from files. It currently vendors a mutated version of the remote-syslog2 library. The mutation is to enable filtering of logs forwarded by blackbox, and to allow us to support structured data in windows-syslog-release, which is purely reliant on blackbox. At some point it might be worthwhile to PR those changes back up; the current situation is admittedly odd and awkward.

RSYSLOG itself might be able to do this at some point in the future. The current version of rsyslog does not sufficiently support wildcards for our use-case, but it may be worth further exploring in the future.


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/ to create the director. Afterwards execute source to target the bosh director.

(Alternatively, if you wish to run the specs against the CI env, you can source the .envrc in your env-repo.)

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

For more details, see tests/

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


Our CI pipelines can be found at Pipeline configuration can be found in the .concourse directory of this repo. While our pipeline is principally built using cf-deployment-concourse-tasks, there are also a couple of unique tasks found in the .concourse/tasks directory.

Use of the ci requires access to the following secrets:

You will also need a concourse to run the pipeline on. Ours is deployed on GCP; the deployment manifest and bbl-state can be found in leela-env.

Most people don't have access to these private repos. The Cloud Foundry Foundation admin team can grant access.

Admin rights to the GCP projects associated with the above env-repos is governed by membership in the Google Group. There are other resources (such as durandal-env, our GCP project for experimental integrations and manual testing) associated with this, as well.