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Merge pull request #339 from jpetazzo/replace-es-with-httpenv

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Replace ElasticSearch with jpetazzo/httpenv
This commit is contained in:
Bridget Kromhout
2018-09-28 08:05:15 -05:00
committed by GitHub
parent 63b85da4f6 db8e8377ac
commit 0d5da73c74
1 changed files with 24 additions and 24 deletions
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48
slides/k8s/kubectlexpose.md
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@@ -59,9 +59,9 @@ Under the hood: `kube-proxy` is using a userland proxy and a bunch of `iptables`
.exercise[
- Start a bunch of ElasticSearch containers:
- Start a bunch of HTTP servers:
```bash
kubectl run elastic --image=elasticsearch:2 --replicas=7
kubectl run httpenv --image=jpetazzo/httpenv --replicas=10
```
- Watch them being started:
@@ -70,15 +70,17 @@ Under the hood: `kube-proxy` is using a userland proxy and a bunch of `iptables`
```
<!--
```wait elastic-```
```wait httpenv-```
```keys ^C```
-->
]
The `-w` option "watches" events happening on the specified resources.
The `jpetazzo/httpenv` image runs an HTTP server on port 8888.
<br/>
It serves its environment variables in JSON format.
Note: please DO NOT call the service `search`. It would collide with the TLD.
The `-w` option "watches" events happening on the specified resources.
---
@@ -88,9 +90,9 @@ Note: please DO NOT call the service `search`. It would collide with the TLD.
.exercise[
- Expose the ElasticSearch HTTP API port:
- Expose the HTTP port of our server:
```bash
kubectl expose deploy/elastic --port 9200
kubectl expose deploy/httpenv --port 8888
```
- Look up which IP address was allocated:
@@ -122,36 +124,34 @@ Note: please DO NOT call the service `search`. It would collide with the TLD.
## Testing our service
- We will now send a few HTTP requests to our ElasticSearch pods
- We will now send a few HTTP requests to our pods
.exercise[
- Let's obtain the IP address that was allocated for our service, *programmatically:*
```bash
IP=$(kubectl get svc elastic -o go-template --template '{{ .spec.clusterIP }}')
IP=$(kubectl get svc httpenv -o go-template --template '{{ .spec.clusterIP }}')
```
<!--
```hide kubectl wait deploy elastic --for condition=available```
```hide sleep 5``` (give some time for elasticsearch to start... hopefully this is enough!)
```hide kubectl wait deploy httpenv --for condition=available```
-->
- Send a few requests:
```bash
curl http://$IP:9200/
curl http://$IP:8888/
```
- Too much output? Filter it with `jq`:
```bash
curl -s http://$IP:8888/ | jq .HOSTNAME
```
]
--
We may see `curl: (7) Failed to connect to _IP_ port 9200: Connection refused`.
This is normal while the service starts up.
--
Once it's running, our requests are load balanced across multiple pods.
Our requests are load balanced across multiple pods.
---
@@ -205,9 +205,9 @@ class: extra-details
.exercise[
- Check the endpoints that Kubernetes has associated with our `elastic` service:
- Check the endpoints that Kubernetes has associated with our `httpenv` service:
```bash
kubectl describe service elastic
kubectl describe service httpenv
```
]
@@ -229,15 +229,15 @@ class: extra-details
- If we want to see the full list, we can use one of the following commands:
```bash
kubectl describe endpoints elastic
kubectl get endpoints elastic -o yaml
kubectl describe endpoints httpenv
kubectl get endpoints httpenv -o yaml
```
- These commands will show us a list of IP addresses
- These IP addresses should match the addresses of the corresponding pods:
```bash
kubectl get pods -l run=elastic -o wide
kubectl get pods -l run=httpenv -o wide
```
---