Specify backend servers' weight via annotation for kubernetes

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Kim Min 2018-07-01 17:26:03 +08:00 committed by Traefiker Bot
parent f9b1106df2
commit e8e36bd9d5
8 changed files with 1055 additions and 2 deletions

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@ -155,9 +155,11 @@ The following general annotations are applicable on the Ingress object:
| `traefik.ingress.kubernetes.io/redirect-replacement: http://mydomain/$1` | Redirect to another URL for that frontend. Must be set with `traefik.ingress.kubernetes.io/redirect-regex`. |
| `traefik.ingress.kubernetes.io/rewrite-target: /users` | Replaces each matched Ingress path with the specified one, and adds the old path to the `X-Replaced-Path` header. |
| `traefik.ingress.kubernetes.io/rule-type: PathPrefixStrip` | Override the default frontend rule type. Default: `PathPrefix`. |
| `traefik.ingress.kubernetes.io/whitelist-source-range: "1.2.3.0/24, fe80::/16"` | A comma-separated list of IP ranges permitted for access. all source IPs are permitted if the list is empty or a single range is ill-formatted. Please note, you may have to set `service.spec.externalTrafficPolicy` to the value `Local` to preserve the source IP of the request for filtering. Please see [this link](https://kubernetes.io/docs/tutorials/services/source-ip/) for more information.|
| `traefik.ingress.kubernetes.io/whitelist-source-range: "1.2.3.0/24, fe80::/16"` | A comma-separated list of IP ranges permitted for access (6). |
| `ingress.kubernetes.io/whitelist-x-forwarded-for: "true"` | Use `X-Forwarded-For` header as valid source of IP for the white list. |
| `traefik.ingress.kubernetes.io/app-root: "/index.html"` | Redirects all requests for `/` to the defined path. (4) |
| `traefik.ingress.kubernetes.io/service-weights: <YML>` | Set ingress backend weights specified as percentage or decimal numbers in YAML. (5) |
<1> `traefik.ingress.kubernetes.io/error-pages` example:
@ -205,6 +207,39 @@ Non-root paths will not be affected by this annotation and handled normally.
This annotation may not be combined with the `ReplacePath` rule type or any other annotation leveraging that rule type.
Trying to do so leads to an error and the corresponding Ingress object being ignored.
<5> `traefik.ingress.kubernetes.io/service-weights`:
Service weights enable to split traffic across multiple backing services in a fine-grained manner.
A canonical use case are canary releases where a new deployment starts to receive a small percentage of traffic (e.g., 1%) and steadily increases over time as confidence in the new deployment improves.
Example:
```yaml
service_backend1: 12.50%
service_backend2: 12.50%
service_backend3: 75 # Same as 75%, the percentage sign is optional
```
A single service backend definition may be omitted; in this case, Traefik auto-completes that service backend to 100% automatically.
Conveniently, users need not bother to compute the percentage remainder for a main service backend.
For instance, in the example above `service_backend3` does not need to be specified to be assigned 75%.
!!! note
For each service weight given, the Ingress specification must include a backend item with the corresponding `serviceName` and (if given) matching path.
Currently, 3 decimal places for the weight are supported.
An attempt to exceed the precision should be avoided as it may lead to percentage computation flaws and, in consequence, Ingress parsing errors.
For each path definition, this annotation will fail if:
- the sum of backend weights exceeds 100% or
- the sum of backend weights is less than 100% without one or more omitted backends
<6> `traefik.ingress.kubernetes.io/whitelist-source-range`:
All source IPs are permitted if the list is empty or a single range is ill-formatted.
Please note, you may have to set `service.spec.externalTrafficPolicy` to the value `Local` to preserve the source IP of the request for filtering.
Please see [this link](https://kubernetes.io/docs/tutorials/services/source-ip/) for more information.
!!! note
Please note that `traefik.ingress.kubernetes.io/redirect-regex` and `traefik.ingress.kubernetes.io/redirect-replacement` do not have to be set if `traefik.ingress.kubernetes.io/redirect-entry-point` is defined for the redirection (they will not be used in this case).