Routing

Note: This section describes the routing rules of in-mesh services. To configure routing rules for ingress gateways, see Routes and traffic management.

One of the top features of Service Mesh Manager is the ability to fully configure how traffic flows in the service mesh. This kind of routing works in the application layer, and lets you configure sophisticated rules based on URIs, ports, or headers.

In Istio, routing is mostly described in Virtual Services, and then translated to Envoy configuration. Service Mesh Manager covers almost everything that you can describe with Virtual Services, but comes with an easy to understand structure of request matches, routes, and different actions.

You can add routing or redirect rules for requests that match certain criteria, and configure different rules like retry policies, request timeouts, or fault injection.

Rule precedence

Note the following points about how Service Mesh Manager evaluates the routing rules:

• Rules are evaluated in top-down order.
• Rules that match on any traffic are always the last to help avoid rule shadowing.
• Changing the order of rules is not supported in Service Mesh Manager.

When you specify multiple MATCH arguments, they have a logical OR relationship: the rule matches any request that fits one of the match rules. Within a match rule, you can specify multiple rules that have an AND relation. That way you can match requests against a specific URL and an HTTP method, for example.

Set routing using the UI

To create a new routing rule from the dashboard, complete the following steps. You can also edit or delete rules, and you can also view the full YAML configuration of the virtual service.

Note: Rules are evaluated in top-down order. For more details, see Rule precedence.

1. Select the service on the MENU > SERVICES or the MENU > TOPOLOGY page.

2. Select TRAFFIC MANAGEMENT > CREATE NEW.

   

3. By default, the new rule matches every incoming request. Click ADD CUSTOM MATCH to select only specific traffic for the rule based on scheme, method, URI, host, port, or authority.

   When you specify multiple MATCH arguments, they have a logical OR relationship: the rule matches any request that fits one of the match rules. Within a match rule, you can specify multiple rules that have an AND relation. That way you can match requests against a specific URL and an HTTP method, for example.

   For example, the following rule matches GET requests, and PUT requests received on port 8080.

   

4. Set the action you want to execute on the matching requests.

   • You can Route the requests to a specific service. To route a portion of the traffic to a different destination, select ADD DESTINATION and use the WEIGHT parameter to split the traffic between multiple destination services.

     

     Note: If you want to mirror the traffic (that is, send the same requests to multiple destinations), see Mirroring.

   • Alternatively, you can Redirect the traffic to a specific URI. Redirect rules overwrite the Path portion of the URL with this value. Note that the entire path is replaced, irrespective of the request URI being matched as an exact path or prefix. To overwrite the Authority/Host portion of the URL, set the AUTHORITY FIELD as well.

     

5. Set TIMEOUT and RETRY options as needed for your environment.

   

6. Click Apply. The new rule appears on the TRAFFIC MANAGEMENT tab.

   

   You can later edit or delete the routing rule by clicking the or icons, respectively.