The information on this page is written for Vamp v0.9.4
Gateways are dynamic runtime entities in the Vamp eco-system defined by ports (incoming) and routes (outgoing). They represent load balancer rules to deployment, cluster and service instances. There are two types of Vamp gateway: Gateways allows for programmable routing.
- Internal gateways created automatically for each deployment cluster and shared by all services deployed within it. Used to distribute traffic for canary releasing and A/B testing across service variants.
- External gateways explicitly declared either in a deployment blueprint or using the gateways API. Provide a stable entry point to a defined, existing route or routes.
Each gateway defines a set of rules for filtering and distributing traffic across the included routes and can optionally be set as sticky. You can access internal and external gateways through Vamp reverse proxy.
On this page:
Route weight and condition strength
Each route in a gateway has a weight and optionally one or more conditions with a
condition_strength (used to target specific traffic for routing). Read more about conditions
Routing is calculated as followed:
- Vamp will first check for a condition that matches the incoming request.
for example, IOS users
- If a matching condition is found, Vamp will check the
condition_strength. The condition strength specifies the percentage of traffic matching the condition to target.
for example, 10% of IOS
- Finally, if no matching condition was found or the request was not selected for routing based on the conditionstrength, it will be routed according to the route weight of all available routes.
for example, all non-IOS traffic and 90% of IOS users are routed according to route weight
Route weights must always total 100%
Vamp has to account for all traffic.
When defining weights, the total weight of all routes must always add up to 100%. This means that in a straight three-way split one service must be given 34% as
33%+33%+33%=99% - 1% can be a lot of traffic in high volume environments.
Example - Route all
Firefox and only
Firefox users to route
service_A: weight: 100% service_B: weight: 0% condition_strength: 100% condition: user-agent == Firefox
Example - Route half of
Firefox users to
service_B, other half to
service_A (80%) or
Firefox requests will be just sent to
service_A (80%) or
service_A: weight: 80% service_B: weight: 20% condition_strength: 50% condition: user-agent == Firefox
Example - A/B test two deployments using route weight
Below is a basic example, similar to putting both deployments (
sava:1.1.0) in the same cluster.
It is easy to imagine having an older legacy application and the new one and doing a full canary release (or A/B testing) in seamless way by using gateways like this.
name: sava:1.0 gateways: 9050/http: sava/port clusters: sava: services: - breed: name: sava:1.0.0 deployable: magneticio/sava:1.0.0 ports: port: 8080/http scale: cpu: 0.2 memory: 256MB instances: 2
name: sava:1.1 gateways: 9060/http: sava/port clusters: sava: services: - breed: name: sava:1.1.0 deployable: magneticio/sava:1.1.0 ports: port: 8080/http scale: cpu: 0.2 memory: 256MB instances: 2
Gateway (90% / 10%):
name: sava port: 9070/http routes: sava:1.0/sava/port: weight: 90% # condition can be used as well sava:1.1/sava/port: weight: 10%
URL path rewrite
Vamp supports URL path rewrite. This can be a powerful solution in defining service APIs (e.g. RESTful) outside of application service. Path rewrite is defined in the format
path: NEW_PATH if CONDITION, where:
NEW_PATHnew path to be used; HAProxy variables are supported, e.g.
CONDITIONcondition using HAProxy directives, e.g. matching path, method, headers etc.
routes: web/port1: rewrites: - path: a if b web/port2: weight: 100%
Vamp managed and external routes
Vamp managed routes are in the format:
gateway- pointing to another gateway, e.g. it is possible to chain gateways
deployment/cluster- pointing to deployment cluster, i.e. services are not ‘visible’
deployment/cluster/service- pointing to specific service within deployment cluster
All examples above cover only Vamp managed routes.
It is also possible to route traffic to specific IP or hostname and port.
In that case IP or hostname and port need to be specified between brackets, e.g.
[hostname:port] (and double quotes due to Yaml syntax).
name: mesos port: 8080/http sticky: route routes: "[192.168.99.100:5050]": weight: 50% "[localhost:5050]": weight: 50%
Last updated on September 7, 2018