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fix style and grammar 

1. Make plural nouns into same style. See it is `Services` in first sentence and `Pods` in the line 286 , but others are `Service`s and `Pod`s .So change style for these plural nouns for consistency and beauty.
2. Fix minor grammar.
pull/2053/head
Peter Lee 2016-12-27 10:46:48 +08:00 committed by GitHub
parent 67be6311ee
commit 42e015d8f8
1 changed files with 23 additions and 23 deletions
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docs/user-guide/debugging-services.md
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@ -7,8 +7,8 @@ title: Debugging Services
--- ---
An issue that comes up rather frequently for new installations of Kubernetes is An issue that comes up rather frequently for new installations of Kubernetes is
that `Services` are not working properly. You've run all your `Pod`s and that `Services` are not working properly. You've run all your `Pods` and
`Deployment`s, but you get no response when you try to access them. `Deployments`, but you get no response when you try to access them.
This document will hopefully help you to figure out what's going wrong. This document will hopefully help you to figure out what's going wrong.
* TOC * TOC
@ -17,7 +17,7 @@ This document will hopefully help you to figure out what's going wrong.
## Conventions ## Conventions
Throughout this doc you will see various commands that you can run. Some Throughout this doc you will see various commands that you can run. Some
commands need to be run within `Pod`, others on a Kubernetes `Node`, and others commands need to be run within a `Pod`, others on a Kubernetes `Node`, and others
can run anywhere you have `kubectl` and credentials for the cluster. To make it can run anywhere you have `kubectl` and credentials for the cluster. To make it
clear what is expected, this document will use the following conventions. clear what is expected, this document will use the following conventions.
@ -71,7 +71,7 @@ $ kubectl exec -ti <POD-NAME> -c <CONTAINER-NAME> sh
## Setup ## Setup
For the purposes of this walk-through, let's run some `Pod`s. Since you're For the purposes of this walk-through, let's run some `Pods`. Since you're
probably debugging your own `Service` you can substitute your own details, or you probably debugging your own `Service` you can substitute your own details, or you
can follow along and get a second data point. can follow along and get a second data point.
@ -109,7 +109,7 @@ spec:
protocol: TCP protocol: TCP
``` ```
Confirm your `Pod`s are running: Confirm your `Pods` are running:
```shell ```shell
$ kubectl get pods -l app=hostnames $ kubectl get pods -l app=hostnames
@ -196,7 +196,7 @@ Address: 10.0.1.175
``` ```
If this fails, perhaps your `Pod` and `Service` are in different If this fails, perhaps your `Pod` and `Service` are in different
`Namespace`s, try a namespace-qualified name: `Namespaces`, try a namespace-qualified name:
```shell ```shell
u@pod$ nslookup hostnames.default u@pod$ nslookup hostnames.default
@ -207,7 +207,7 @@ Name: hostnames.default
Address: 10.0.1.175 Address: 10.0.1.175
``` ```
If this works, you'll need to ensure that `Pod`s and `Service`s run in the same If this works, you'll need to ensure that `Pods` and `Services` run in the same
`Namespace`. If this still fails, try a fully-qualified name: `Namespace`. If this still fails, try a fully-qualified name:
```shell ```shell
@ -326,18 +326,18 @@ $ kubectl get service hostnames -o json
``` ```
Is the port you are trying to access in `spec.ports[]`? Is the `targetPort` Is the port you are trying to access in `spec.ports[]`? Is the `targetPort`
correct for your `Pod`s? If you meant it to be a numeric port, is it a number correct for your `Pods`? If you meant it to be a numeric port, is it a number
(9376) or a string "9376"? If you meant it to be a named port, do your `Pod`s (9376) or a string "9376"? If you meant it to be a named port, do your `Pods`
expose a port with the same name? Is the port's `protocol` the same as the expose a port with the same name? Is the port's `protocol` the same as the
`Pod`'s? `Pod`'s?
## Does the Service have any Endpoints? ## Does the Service have any Endpoints?
If you got this far, we assume that you have confirmed that your `Service` If you got this far, we assume that you have confirmed that your `Service`
exists and resolves by DNS. Now let's check that the `Pod`s you ran are exists and is resolved by DNS. Now let's check that the `Pods` you ran are
actually being selected by the `Service`. actually being selected by the `Service`.
Earlier we saw that the `Pod`s were running. We can re-check that: Earlier we saw that the `Pods` were running. We can re-check that:
```shell ```shell
$ kubectl get pods -l app=hostnames $ kubectl get pods -l app=hostnames
@ -347,7 +347,7 @@ hostnames-bvc05 1/1 Running 0 1h
hostnames-yp2kp 1/1 Running 0 1h hostnames-yp2kp 1/1 Running 0 1h
``` ```
The "AGE" column says that these `Pod`s are about an hour old, which implies that The "AGE" column says that these `Pods` are about an hour old, which implies that
they are running fine and not crashing. they are running fine and not crashing.
The `-l app=hostnames` argument is a label selector - just like our `Service` The `-l app=hostnames` argument is a label selector - just like our `Service`
@ -360,16 +360,16 @@ NAME ENDPOINTS
hostnames 10.244.0.5:9376,10.244.0.6:9376,10.244.0.7:9376 hostnames 10.244.0.5:9376,10.244.0.6:9376,10.244.0.7:9376
``` ```
This confirms that the control loop has found the correct `Pod`s for your This confirms that the control loop has found the correct `Pods` for your
`Service`. If the `hostnames` row is blank, you should check that the `Service`. If the `hostnames` row is blank, you should check that the
`spec.selector` field of your `Service` actually selects for `metadata.labels` `spec.selector` field of your `Service` actually selects for `metadata.labels`
values on your `Pod`s. values on your `Pods`.
## Are the Pods working? ## Are the Pods working?
At this point, we know that your `Service` exists and has selected your `Pod`s. At this point, we know that your `Service` exists and has selected your `Pods`.
Let's check that the `Pod`s are actually working - we can bypass the `Service` Let's check that the `Pods` are actually working - we can bypass the `Service`
mechanism and go straight to the `Pod`s. mechanism and go straight to the `Pods`.
```shell ```shell
u@pod$ wget -qO- 10.244.0.5:9376 u@pod$ wget -qO- 10.244.0.5:9376
@ -384,19 +384,19 @@ hostnames-yp2kp
We expect each `Pod` in the `Endpoints` list to return its own hostname. If We expect each `Pod` in the `Endpoints` list to return its own hostname. If
this is not what happens (or whatever the correct behavior is for your own this is not what happens (or whatever the correct behavior is for your own
`Pod`s), you should investigate what's happening there. You might find `Pods`), you should investigate what's happening there. You might find
`kubectl logs` to be useful or `kubectl exec` directly to your `Pod`s and check `kubectl logs` to be useful or `kubectl exec` directly to your `Pods` and check
service from there. service from there.
## Is the kube-proxy working? ## Is the kube-proxy working?
If you get here, your `Service` is running, has `Endpoints`, and your `Pod`s If you get here, your `Service` is running, has `Endpoints`, and your `Pods`
are actually serving. At this point, the whole `Service` proxy mechanism is are actually serving. At this point, the whole `Service` proxy mechanism is
suspect. Let's confirm it, piece by piece. suspect. Let's confirm it, piece by piece.
### Is kube-proxy running? ### Is kube-proxy running?
Confirm that `kube-proxy` is running on your `Node`s. You should get something Confirm that `kube-proxy` is running on your `Nodes`. You should get something
like the below: like the below:
```shell ```shell
@ -429,7 +429,7 @@ should double-check your `Node` configuration and installation steps.
### Is kube-proxy writing iptables rules? ### Is kube-proxy writing iptables rules?
One of the main responsibilities of `kube-proxy` is to write the `iptables` One of the main responsibilities of `kube-proxy` is to write the `iptables`
rules which implement `Service`s. Let's check that those rules are getting rules which implement `Services`. Let's check that those rules are getting
written. written.
The kube-proxy can run in either "userspace" mode or "iptables" mode. The kube-proxy can run in either "userspace" mode or "iptables" mode.
@ -620,7 +620,7 @@ UP BROADCAST RUNNING PROMISC MULTICAST MTU:1460 Metric:1
## Seek help ## Seek help
If you get this far, something very strange is happening. Your `Service` is If you get this far, something very strange is happening. Your `Service` is
running, has `Endpoints`, and your `Pod`s are actually serving. You have DNS running, has `Endpoints`, and your `Pods` are actually serving. You have DNS
working, `iptables` rules installed, and `kube-proxy` does not seem to be working, `iptables` rules installed, and `kube-proxy` does not seem to be
misbehaving. And yet your `Service` is not working. You should probably let misbehaving. And yet your `Service` is not working. You should probably let
us know, so we can help investigate! us know, so we can help investigate!