第 14 章 Configuring Routes
14.1. Route configuration
14.1.1. Configuring route timeouts
You can configure the default timeouts for an existing route when you have services in need of a low timeout, which is required for Service Level Availability (SLA) purposes, or a high timeout, for cases with a slow back end.
Prerequisites
- You need a deployed Ingress Controller on a running cluster.
Procedure
Using the
oc annotatecommand, add the timeout to the route:$ oc annotate route <route_name> \ --overwrite haproxy.router.openshift.io/timeout=<timeout><time_unit> 1- 1
- Supported time units are microseconds (us), milliseconds (ms), seconds (s), minutes (m), hours (h), or days (d).
The following example sets a timeout of two seconds on a route named
myroute:$ oc annotate route myroute --overwrite haproxy.router.openshift.io/timeout=2s
14.1.2. Enabling HTTP strict transport security
HTTP Strict Transport Security (HSTS) policy is a security enhancement, which ensures that only HTTPS traffic is allowed on the host. Any HTTP requests are dropped by default. This is useful for ensuring secure interactions with websites, or to offer a secure application for the user’s benefit.
When HSTS is enabled, HSTS adds a Strict Transport Security header to HTTPS responses from the site. You can use the insecureEdgeTerminationPolicy value in a route to redirect to send HTTP to HTTPS. However, when HSTS is enabled, the client changes all requests from the HTTP URL to HTTPS before the request is sent, eliminating the need for a redirect. This is not required to be supported by the client, and can be disabled by setting max-age=0.
HSTS works only with secure routes (either edge terminated or re-encrypt). The configuration is ineffective on HTTP or passthrough routes.
Procedure
To enable HSTS on a route, add the
haproxy.router.openshift.io/hsts_headervalue to the edge terminated or re-encrypt route:apiVersion: v1 kind: Route metadata: annotations: haproxy.router.openshift.io/hsts_header: max-age=31536000;includeSubDomains;preload 1 2 3- 1
max-ageis the only required parameter. It measures the length of time, in seconds, that the HSTS policy is in effect. The client updatesmax-agewhenever a response with a HSTS header is received from the host. Whenmax-agetimes out, the client discards the policy.- 2
includeSubDomainsis optional. When included, it tells the client that all subdomains of the host are to be treated the same as the host.- 3
preloadis optional. Whenmax-ageis greater than 0, then includingpreloadinhaproxy.router.openshift.io/hsts_headerallows external services to include this site in their HSTS preload lists. For example, sites such as Google can construct a list of sites that havepreloadset. Browsers can then use these lists to determine which sites they can communicate with over HTTPS, before they have interacted with the site. Withoutpreloadset, browsers must have interacted with the site over HTTPS to get the header.
14.1.3. Troubleshooting throughput issues
Sometimes applications deployed through OpenShift Container Platform can cause network throughput issues such as unusually high latency between specific services.
Use the following methods to analyze performance issues if pod logs do not reveal any cause of the problem:
Use a packet analyzer, such as ping or tcpdump to analyze traffic between a pod and its node.
For example, run the tcpdump tool on each pod while reproducing the behavior that led to the issue. Review the captures on both sides to compare send and receive timestamps to analyze the latency of traffic to and from a pod. Latency can occur in OpenShift Container Platform if a node interface is overloaded with traffic from other pods, storage devices, or the data plane.
$ tcpdump -s 0 -i any -w /tmp/dump.pcap host <podip 1> && host <podip 2> 1- 1
podipis the IP address for the pod. Run theoc get pod <pod_name> -o widecommand to get the IP address of a pod.
tcpdump generates a file at
/tmp/dump.pcapcontaining all traffic between these two pods. Ideally, run the analyzer shortly before the issue is reproduced and stop the analyzer shortly after the issue is finished reproducing to minimize the size of the file. You can also run a packet analyzer between the nodes (eliminating the SDN from the equation) with:$ tcpdump -s 0 -i any -w /tmp/dump.pcap port 4789
Use a bandwidth measuring tool, such as iperf, to measure streaming throughput and UDP throughput. Run the tool from the pods first, then from the nodes, to locate any bottlenecks.
- For information on installing and using iperf, see this Red Hat Solution.
14.1.4. Using cookies to keep route statefulness
OpenShift Container Platform provides sticky sessions, which enables stateful application traffic by ensuring all traffic hits the same endpoint. However, if the endpoint pod terminates, whether through restart, scaling, or a change in configuration, this statefulness can disappear.
OpenShift Container Platform can use cookies to configure session persistence. The Ingress controller selects an endpoint to handle any user requests, and creates a cookie for the session. The cookie is passed back in the response to the request and the user sends the cookie back with the next request in the session. The cookie tells the Ingress Controller which endpoint is handling the session, ensuring that client requests use the cookie so that they are routed to the same pod.
14.1.4.1. Annotating a route with a cookie
You can set a cookie name to overwrite the default, auto-generated one for the route. This allows the application receiving route traffic to know the cookie name. By deleting the cookie it can force the next request to re-choose an endpoint. So, if a server was overloaded it tries to remove the requests from the client and redistribute them.
Procedure
Annotate the route with the specified cookie name:
$ oc annotate route <route_name> router.openshift.io/cookie_name="<cookie_name>"
where:
<route_name>- Specifies the name of the route.
<cookie_name>- Specifies the name for the cookie.
For example, to annotate the route
my_routewith the cookie namemy_cookie:$ oc annotate route my_route router.openshift.io/cookie_name="my_cookie"
Capture the route host name in a variable:
$ ROUTE_NAME=$(oc get route <route_name> -o jsonpath='{.spec.host}')where:
<route_name>- Specifies the name of the route.
Save the cookie, and then access the route:
$ curl $ROUTE_NAME -k -c /tmp/cookie_jar
Use the cookie saved by the previous command when connecting to the route:
$ curl $ROUTE_NAME -k -b /tmp/cookie_jar
14.1.5. Path-based routes
Path-based routes specify a path component that can be compared against a URL, which requires that the traffic for the route be HTTP based. Thus, multiple routes can be served using the same host name, each with a different path. Routers should match routes based on the most specific path to the least. However, this depends on the router implementation.
The following table shows example routes and their accessibility:
| Route | When Compared to | Accessible |
|---|---|---|
| www.example.com/test | www.example.com/test | Yes |
| www.example.com | No | |
| www.example.com/test and www.example.com | www.example.com/test | Yes |
| www.example.com | Yes | |
| www.example.com | www.example.com/text | Yes (Matched by the host, not the route) |
| www.example.com | Yes |
An unsecured route with a path
apiVersion: v1
kind: Route
metadata:
name: route-unsecured
spec:
host: www.example.com
path: "/test" 1
to:
kind: Service
name: service-name
- 1
- The path is the only added attribute for a path-based route.
Path-based routing is not available when using passthrough TLS, as the router does not terminate TLS in that case and cannot read the contents of the request.
14.1.6. Route-specific annotations
The Ingress Controller can set the default options for all the routes it exposes. An individual route can override some of these defaults by providing specific configurations in its annotations. Red Hat does not support adding a route annotation to an operator-managed route.
To create a whitelist with multiple source IPs or subnets, use a space-delimited list. Any other delimiter type causes the list to be ignored without a warning or error message.
| Variable | Description | Environment variable used as default |
|---|---|---|
|
|
Sets the load-balancing algorithm. Available options are |
|
|
|
Disables the use of cookies to track related connections. If set to | |
|
| Specifies an optional cookie to use for this route. The name must consist of any combination of upper and lower case letters, digits, "_", and "-". The default is the hashed internal key name for the route. | |
|
| Sets the maximum number of connections that are allowed to a backing pod from a router. Note: if there are multiple pods, each can have this many connections. But if you have multiple routers, there is no coordination among them, each may connect this many times. If not set, or set to 0, there is no limit. | |
|
|
Setting | |
|
| Limits the number of concurrent TCP connections shared by an IP address. | |
|
| Limits the rate at which an IP address can make HTTP requests. | |
|
| Limits the rate at which an IP address can make TCP connections. | |
|
| Sets a server-side timeout for the route. (TimeUnits) |
|
|
| Sets the interval for the back-end health checks. (TimeUnits) |
|
|
| Sets a whitelist for the route. The whitelist is a space-separated list of IP addresses and CIDR ranges for the approved source addresses. Requests from IP addresses that are not in the whitelist are dropped. The maximum number of IP addresses and CIDR ranges allowed in a whitelist is 61. | |
|
| Sets a Strict-Transport-Security header for the edge terminated or re-encrypt route. | |
|
|
Sets the |
Environment variables cannot be edited.
A route setting custom timeout
apiVersion: v1
kind: Route
metadata:
annotations:
haproxy.router.openshift.io/timeout: 5500ms 1
...
- 1
- Specifies the new timeout with HAProxy supported units (
us,ms,s,m,h,d). If the unit is not provided,msis the default.
Setting a server-side timeout value for passthrough routes too low can cause WebSocket connections to timeout frequently on that route.
A route that allows only one specific IP address
metadata:
annotations:
haproxy.router.openshift.io/ip_whitelist: 192.168.1.10
A route that allows several IP addresses
metadata:
annotations:
haproxy.router.openshift.io/ip_whitelist: 192.168.1.10 192.168.1.11 192.168.1.12
A route that allows an IP address CIDR network
metadata:
annotations:
haproxy.router.openshift.io/ip_whitelist: 192.168.1.0/24
A route that allows both IP an address and IP address CIDR networks
metadata:
annotations:
haproxy.router.openshift.io/ip_whitelist: 180.5.61.153 192.168.1.0/24 10.0.0.0/8
14.1.7. Configuring the route admission policy
Administrators and application developers can run applications in multiple namespaces with the same domain name. This is for organizations where multiple teams develop microservices that are exposed on the same host name.
Allowing claims across namespaces should only be enabled for clusters with trust between namespaces, otherwise a malicious user could take over a host name. For this reason, the default admission policy disallows host name claims across namespaces.
Prerequisites
- Cluster administrator privileges.
Procedure
Edit the
.spec.routeAdmissionfield of theingresscontrollerresource variable using the following command:$ oc -n openshift-ingress-operator patch ingresscontroller/default --patch '{"spec":{"routeAdmission":{"namespaceOwnership":"InterNamespaceAllowed"}}}' --type=mergeSample Ingress Controller configuration
spec: routeAdmission: namespaceOwnership: InterNamespaceAllowed ...
