marathon-consul 
We no longer develop this project. If you'd like to take over and continue its maintenance, please fork this repository and let us know by Github issues.
Register Marathon Tasks as Consul Services for service discovery.
marathon-consul takes information provided by the Marathon event bus and forwards it to Consul agents. It also re-syncs all the information from Marathon to Consul on startup and repeats it with given interval.
Note: In the future release Event Bus (callbacks) will be considered deprecated and eventually removed in favor of Event Stream (SSE). Right now marathon-consul is supporting both solutions. SSE is provided as experimental feature, disabled by default (more).
Code
This project is based on
Differences
- CiscoCloud/marathon-consul copies application information to Consul KV while allegro/marathon-consul registers tasks as Consul services (it is more similar to CiscoCloud/mesos-consul)
- CiscoCloud/mesos-consul uses polling while allegro/marathon-consul uses Marathon's event bus to detect changes
- CiscoCloud/marathon-consul is no longer developed (see comment)
Installation
Installing from source code
To simply compile and run the source code:
go run main.go [options]
To run the tests:
make test
To build the binary:
make build
Installing from binary distribution
Binary distribution of marathon-consul can be downloaded directly from the releases page. Download the build dedicated to your OS. After unpacking the archive, run marathon-consul binary. You can also add some options, for example:
marathon-consul --marathon-location=marathon.service.consul:8080 --sync-interval=5m --log-level=debug
Installing via APT package manager
If you are a Debian/Ubuntu user, you can easily install marathon-consul as a deb package using APT package manager. Both upstart and systemd service managers are supported. All releases are published as deb packages to our repository at Bintray.
To install marathon-consul with apt-get, simply follow the instructions:
# add our public key to apt
curl -s https://bintray.com/user/downloadSubjectPublicKey?username=allegro | sudo apt-key add -
# add the repository url
echo "deb http://dl.bintray.com/v1/content/allegro/deb /" | sudo tee /etc/apt/sources.list.d/marathon-consul.list
# update apt cache
sudo apt-get -y update
# install latest release of marathon-consul
sudo apt-get -qy install marathon-consul
Run it with service marathon-consul start. The configuration file is located at /etc/marathon-consul.d/config.json.
Installing with Docker
To build docker image run
make docker
Then you can run it with
docker run -d -P allegro/marathon-consul [options]
If you want to use SSL you will need to expose cert store to Docker. The Following line is only example, your cert store might be different depending on your system.
docker run '/etc/ssl/certs/ca-certificates.crt:/etc/ssl/certs/ca-certificates.crt' -P allegro/marathon-consul
Usage
Marathon masters
- marathon-consul should be installed on all Marathon masters
Mesos agents
- Consul Agents should be available on every Mesos agent.
- Tasks will be registered at the Mesos slave they run on.
Tagging tasks
- Task labels are used by marathon-consul to register tasks in Consul.
- Only tasks which are labeled as
consulwill be registered in Consul. If theconsullabel is left blank like"consul": "", the task will be registered with the app name by default. A different name can be provided as the label's value, e.g."consul": "customName". As an exception to this rule, for backward compatibility with the0.3.xbranch, a value oftrueis resolved to the default name.
"id": "my-new-app",
"labels": {
"consul": ""
}
- Only services with tag specified by
consul-tagproperty will be maintained. By default,"consul-tag": "marathon"is automatically added when the task is registered. - Labels with a value of
tagare converted to consul-tags, and appear in Consul as ServiceTags. - For example, we can set these tags in an app definition like:
"id": "my-new-app",
"labels": {
"consul": "",
"varnish": "tag",
"metrics": "tag"
}
- If marathon-consul registers the app with Consul, we can then query Consul and see these tags appear:
curl -X GET http://localhost:8500/v1/catalog/service/my-new-app
...
"ServiceName": "my-new-app",
"ServiceTags": [
"marathon",
"varnish",
"metrics",
"marathon-task:my-new-app.6a95bb03-6ad3-11e6-beaf-080027a7aca0"
],
- Every service registration contains an additional tag
marathon-taskspecifying the Marathon task id related to this registration. - If there are multiple ports in use for the same app, note that only the first one will be registered by marathon-consul in Consul.
If you need to register your task under multiple ports, refer to Advanced usage section below.
Task healthchecks
- At least one HTTP healthcheck should be defined for a task. The task is registered when Marathon marks it as alive.
- The provided HTTP healthcheck will be transferred to Consul.
- See this for more details.
Command healthchecks
Healthchecks commands are registered in Consul with a simple variable substitution.
- $HOST is replaced by task hostname.
- $PORT0, $PORT1... are replaced by port number defined in task.
Using a special shell syntax can break this variable substitution ($HOST, ${PORT0} ...)
Sync
- The scheduled Marathon-consul sync may run in two modes:
- Only on node that is the current Marathon-leader,
marathon-leaderparameter should be set tohostname:portthe current node appears in the Marathon cluster. This mode is enabled by default and themarathon-leaderproperty is set to the hostname resolved by OS. Note that there is a difference betweenmarathon-leaderandmarathon-location:marathon-leaderis used for node leadership detection (should be set to cluster-wide node name), whilemarathon-locationis used for connection purpose (may be set tolocalhost) - On every node,
sync-forceparameter should be set totrue
- Only on node that is the current Marathon-leader,
- If marathon-consul fails on startup sync and you see following error
"Can't get Consul services: No Consul client available in agents cache"it may be caused by empty consul agents cache. If this occurs try configuring--consul-local-agent-hostto Consul Master or Consul agent.
Options
| Argument | Default | Description |
|---|---|---|
| config-file | Path to a JSON file to read configuration from. Note: Will override options set earlier on the command line | |
| consul-auth | false |
Use Consul with authentication |
| consul-auth-password | The basic authentication password | |
| consul-auth-username | The basic authentication username | |
| consul-enable-tag-override | false |
Disable the anti-entropy feature for all services |
| consul-ignored-healthchecks | A comma separated blacklist of Marathon health check types that will not be migrated to Consul, e.g. command,tcp | |
| consul-local-agent-host | Consul Agent hostname or IP that should be used for startup sync and service listing operations | |
| consul-name-separator | . |
Separator used to create default service name for Consul |
| consul-get-services-retry | 3 |
Number of retries on failure when performing requests to Consul. Each retry uses different cached agent |
| consul-max-agent-failures | 3 |
Max number of consecutive request failures for agent before removal from cache |
| consul-port | 8500 |
Consul port |
| consul-ssl | false |
Use HTTPS when talking to Consul |
| consul-ssl-ca-cert | Path to a CA certificate file, containing one or more CA certificates to use to validate the certificate sent by the Consul server to us | |
| consul-ssl-cert | Path to an SSL client certificate to use to authenticate to the Consul server | |
| consul-ssl-verify | true |
Verify certificates when connecting via SSL |
| consul-tag | marathon |
Common tag name added to every service registered in Consul, should be unique for every Marathon-cluster connected to Consul |
| consul-timeout | 3s |
Time limit for requests made by the Consul HTTP client. A Timeout of zero means no timeout |
| consul-token | The Consul ACL token | |
| events-queue-size | 1000 |
Size of events queue |
| event-max-size | 4096 |
Maximum size of event to process (bytes) |
| listen | :4000 |
Accept connections at this address |
| log-file | Save logs to file (e.g.: /var/log/marathon-consul.log). If empty logs are published to STDERR |
|
| log-format | text |
Log format: JSON, text |
| log-level | info |
Log level: panic, fatal, error, warn, info, or debug |
| marathon-location | localhost:8080 |
Marathon URL |
| marathon-password | Marathon password for basic auth | |
| marathon-protocol | http |
Marathon protocol (http or https) |
| marathon-ssl-verify | true |
Verify certificates when connecting via SSL |
| marathon-timeout | 30s |
Time limit for requests made by the Marathon HTTP client. A Timeout of zero means no timeout |
| marathon-username | Marathon username for basic auth | |
| marathon-leader | Marathon cluster-wide node name (defaults to :8080), the some leader specific calls will be made only if the specified node is the current Marathon-leader. Set to * to always act like a Leader. |
|
| metrics-interval | 30s |
Metrics reporting interval |
| metrics-location | Graphite URL (used when metrics-target is set to graphite) | |
| metrics-prefix | default |
Metrics prefix (default is resolved to .<app_name> |
| metrics-target | stdout |
Metrics destination stdout or graphite (empty string disables metrics) |
| sentry-dsn | Sentry DSN. If it's not set sentry will be disabled | |
| sentry-env | Sentry environment | |
| sentry-level | error |
Sentry alerting level (info |
| sentry-timeout | 1s |
Sentry hook initialization timeout |
| sse-retries | 0 |
Number of times to recover SSE stream. |
| sse-retry-backoff | 0s |
Configuration of initial time between retries to recover SSE stream. |
| sync-enabled | true |
Enable Marathon-consul scheduled sync |
| sync-force | false |
Force leadership-independent Marathon-consul sync (run always) |
| sync-interval | 15m0s |
Marathon-consul sync interval |
| workers-pool-size | 10 |
Number of concurrent workers processing events |
Endpoints
| Endpoint | Description |
|---|---|
/health |
healthcheck - returns OK |
Advanced usage
Register under multiple ports
If you need to map your Marathon task into multiple service registrations in Consul, you can configure marathon-consul via Marathon's portDefinitions:
"id": "my-new-app",
"labels": {
"consul": "",
"common-tag": "tag"
},
"portDefinitions": [
{
"labels": {
"consul": "my-app-custom-name"
}
},
{
"labels": {
"consul": "my-app-other-name",
"specific-tag": "tag"
}
}
]
This configuration would result in two service registrations:
curl -X GET http://localhost:8500/v1/catalog/service/my-app-custom-name
...
"ServiceName": "my-app-custom-name",
"ServiceTags": [
"marathon",
"common-tag",
"marathon-task:my-new-app.6a95bb03-6ad3-11e6-beaf-080027a7aca0"
],
"ServicePort": 31292,
...
curl -X GET http://localhost:8500/v1/catalog/service/my-app-other-name
...
"ServiceName": "my-app-other-name",
"ServiceTags": [
"marathon",
"common-tag",
"specific-tag",
"marathon-task:my-new-app.6a95bb03-6ad3-11e6-beaf-080027a7aca0"
],
"ServicePort": 31293,
...
If any port definition contains the consul label, then advanced configuration mode is enabled. As a result, only the ports containing this label are registered, under the name specified as the label's value – with empty value resolved to default name. Names don't have to be unique – you can have multiple registrations under the same name, but on different ports, perhaps with different tags. Note that the consul label still needs to be present in the top-level application labels, even though its value won't have any effect.
Tags configured in the top-level application labels will be added to all registrations. Tags configured in the port definition labels will be added only to corresponding registrations.
All registrations share the same marathon-task tag.
Migration to version 1.x.x
Until 1.x.x marathon-consul would register services in Consul with registration id equal to related Marathon task id. Since 1.x.x registration ids are different and an additional tag, marathon-task, is added to each registration.
If you update marathon-consul from version 0.x.x to 1.x.x, expect the synchronization phase during the first startup to reregister all healthy services managed by marathon-consul to the new format. Unhealthy services will get deregistered in the process.
SSE Support
While using SSE please consider:
- SSE is using Web module config for queues, event sizes, in the future will be moved to sse module,
- SSE is using marathon-leader config for determining current leader, when this value match leader returned by marathon (/v2/leader endpoint) then SSE is started on this instance,
- when enabled SSE is spawning its own own set of workers and separated dispatcher,
- be advised to disable marathon callback subscription when enabling SSE, otherwise it might result in doubling registers and deregisers.
HTTP callbacks support
Marathon-Consul does not support HTTP callbacks. Marathon deprecated support for HTTP callbacks in 1.4. This mechanism is no longer available starting from Marathon 1.5.
Known limitations
The following section describes known limitations in marathon-consul.
- In Marathon when a deployment changing the application's service name (by changing its
labels) is being stopped, it changes app's configuration anyway. This means we loose the link between the app and the services registered with the old name in Consul. Later on, if another deployment takes place, new services are registered with a new name, the old ones are not being deregistered though. A scheduled sync is required to wipe them out.
Release
To release new version of marathon-consul follow steps:
- Commit all changes you need for release to master branch.
git checkout mastergit checkout -b release/<version>e.g.,git checkout -b release/1.3.1make version v=<version>e.g.,make version v=1.3.1git push- Create pull request from branch
release/<version>to master. - Once pull request gets merged put tag on this commit (remember to update your master with
git pull)git tag <version> -fe.g.,git tag 1.3.1 -f. Create annotated tag with release notes in it. - Travis will automatically prepare github release from tag on master. Go there and update release notes.
- Copy github release to bintray.
License
Marathon-consul is released under the Apache 2.0 license (see LICENSE)
