github/container.training
1
0
Fork 0
mirror of https://github.com/jpetazzo/container.training.git synced 2026-07-28 09:11:18 +00:00
Code Issues Packages Projects Releases Wiki Activity

indexconf2017

Browse Source
This commit is contained in:
Bridget Kromhout
2018-02-18 20:21:55 -06:00
parent 5116ad7c44
commit b25d40f48e
17 changed files with 58 additions and 440 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
slides/common/intro.md
View File

@@ -9,12 +9,10 @@
- We recommend having a mentor to help you ...
- ... Or be comfortable spending some time reading the Docker
[documentation](https://docs.docker.com/) ...
- ... Or be comfortable spending some time reading the Kubernetes
[documentation](https://kubernetes.io/docs/) ...
- ... And looking for answers in the [Docker forums](forums.docker.com),
[StackOverflow](http://stackoverflow.com/questions/tagged/docker),
and other outlets
- ... And looking for answers on [StackOverflow](http://stackoverflow.com/questions/tagged/kubernetes) and other outlets
---

16
slides/common/prereqs.md
View File

@@ -26,7 +26,7 @@ class: extra-details
- This slide should have a little magnifying glass in the top left corner
(If it doesn't, it's because CSS is hard — Jérôme is only a backend person, alas)
(If it doesn't, it's because CSS is hard — we're only backend people, alas!)
- Slides with that magnifying glass indicate slides providing extra details
@@ -62,7 +62,7 @@ Misattributed to Benjamin Franklin
- This is the stuff you're supposed to do!
- Go to [container.training](http://container.training/) to view these slides
- Go to [indexconf2018.container.training](http://indexconf2018.container.training/) to view these slides
- Join the chat room on @@CHAT@@
@@ -78,17 +78,11 @@ class: in-person
---
class: in-person, pic
![You get five VMs](images/you-get-five-vms.jpg)
---
class: in-person
## You get five VMs
## You get three VMs
- Each person gets 5 private VMs (not shared with anybody else)
- Each person gets 3 private VMs (not shared with anybody else)
- They'll remain up for the duration of the workshop
@@ -153,7 +147,7 @@ class: in-person
<!--
```bash
for N in $(seq 1 5); do
for N in $(seq 1 3); do
ssh -o StrictHostKeyChecking=no node$N true
done
```

371
slides/common/sampleapp.md
View File

@@ -21,65 +21,6 @@
---
class: extra-details
## Compose file format version
*Particularly relevant if you have used Compose before...*
- Compose 1.6 introduced support for a new Compose file format (aka "v2")
- Services are no longer at the top level, but under a `services` section
- There has to be a `version` key at the top level, with value `"2"` (as a string, not an integer)
- Containers are placed on a dedicated network, making links unnecessary
- There are other minor differences, but upgrade is easy and straightforward
---
## Links, naming, and service discovery
- Containers can have network aliases (resolvable through DNS)
- Compose file version 2+ makes each container reachable through its service name
- Compose file version 1 did require "links" sections
- Our code can connect to services using their short name
(instead of e.g. IP address or FQDN)
- Network aliases are automatically namespaced
(i.e. you can have multiple apps declaring and using a service named `database`)
---
## Example in `worker/worker.py`
```python
redis = Redis("`redis`")
def get_random_bytes():
r = requests.get("http://`rng`/32")
return r.content
def hash_bytes(data):
r = requests.post("http://`hasher`/",
data=data,
headers={"Content-Type": "application/octet-stream"})
```
(Full source code available [here](
https://github.com/jpetazzo/container.training/blob/8279a3bce9398f7c1a53bdd95187c53eda4e6435/dockercoins/worker/worker.py#L17
))
---
## What's this application?
--
@@ -124,7 +65,7 @@ fi
- Clone the repository on `node1`:
```bash
git clone git://github.com/jpetazzo/container.training
git clone https://github.com/jpetazzo/container.training/
```
]
@@ -183,77 +124,6 @@ and displays aggregated logs.
---
## Restarting in the background
- Many flags and commands of Compose are modeled after those of `docker`
.exercise[
- Start the app in the background with the `-d` option:
```bash
docker-compose up -d
```
- Check that our app is running with the `ps` command:
```bash
docker-compose ps
```
]
`docker-compose ps` also shows the ports exposed by the application.
---
class: extra-details
## Viewing logs
- The `docker-compose logs` command works like `docker logs`
.exercise[
- View all logs since container creation and exit when done:
```bash
docker-compose logs
```
- Stream container logs, starting at the last 10 lines for each container:
```bash
docker-compose logs --tail 10 --follow
```
<!--
```wait units of work done```
```keys ^C```
-->
]
Tip: use `^S` and `^Q` to pause/resume log output.
---
class: extra-details
## Upgrading from Compose 1.6
.warning[The `logs` command has changed between Compose 1.6 and 1.7!]
- Up to 1.6
- `docker-compose logs` is the equivalent of `logs --follow`
- `docker-compose logs` must be restarted if containers are added
- Since 1.7
- `--follow` must be specified explicitly
- new containers are automatically picked up by `docker-compose logs`
---
## Connecting to the web UI
- The `webui` container exposes a web dashboard; let's view it
@@ -275,245 +145,6 @@ graph will appear.
---
class: self-paced, extra-details
## If the graph doesn't load
If you just see a `Page not found` error, it might be because your
Docker Engine is running on a different machine. This can be the case if:
- you are using the Docker Toolbox
- you are using a VM (local or remote) created with Docker Machine
- you are controlling a remote Docker Engine
When you run DockerCoins in development mode, the web UI static files
are mapped to the container using a volume. Alas, volumes can only
work on a local environment, or when using Docker4Mac or Docker4Windows.
How to fix this?
Edit `dockercoins.yml` and comment out the `volumes` section, and try again.
---
class: extra-details
## Why does the speed seem irregular?
- It *looks like* the speed is approximately 4 hashes/second
- Or more precisely: 4 hashes/second, with regular dips down to zero
- Why?
--
class: extra-details
- The app actually has a constant, steady speed: 3.33 hashes/second
<br/>
(which corresponds to 1 hash every 0.3 seconds, for *reasons*)
- Yes, and?
---
class: extra-details
## The reason why this graph is *not awesome*
- The worker doesn't update the counter after every loop, but up to once per second
- The speed is computed by the browser, checking the counter about once per second
- Between two consecutive updates, the counter will increase either by 4, or by 0
- The perceived speed will therefore be 4 - 4 - 4 - 0 - 4 - 4 - 0 etc.
- What can we conclude from this?
--
class: extra-details
- Jérôme is clearly incapable of writing good frontend code
---
## Scaling up the application
- Our goal is to make that performance graph go up (without changing a line of code!)
--
- Before trying to scale the application, we'll figure out if we need more resources
(CPU, RAM...)
- For that, we will use good old UNIX tools on our Docker node
---
## Looking at resource usage
- Let's look at CPU, memory, and I/O usage
.exercise[
- run `top` to see CPU and memory usage (you should see idle cycles)
<!--
```bash top```
```wait Tasks```
```keys ^C```
-->
- run `vmstat 1` to see I/O usage (si/so/bi/bo)
<br/>(the 4 numbers should be almost zero, except `bo` for logging)
<!--
```bash vmstat 1```
```wait memory```
```keys ^C```
-->
]
We have available resources.
- Why?
- How can we use them?
---
## Scaling workers on a single node
- Docker Compose supports scaling
- Let's scale `worker` and see what happens!
.exercise[
- Start one more `worker` container:
```bash
docker-compose scale worker=2
```
- Look at the performance graph (it should show a x2 improvement)
- Look at the aggregated logs of our containers (`worker_2` should show up)
- Look at the impact on CPU load with e.g. top (it should be negligible)
]
---
## Adding more workers
- Great, let's add more workers and call it a day, then!
.exercise[
- Start eight more `worker` containers:
```bash
docker-compose scale worker=10
```
- Look at the performance graph: does it show a x10 improvement?
- Look at the aggregated logs of our containers
- Look at the impact on CPU load and memory usage
]
---
# Identifying bottlenecks
- You should have seen a 3x speed bump (not 10x)
- Adding workers didn't result in linear improvement
- *Something else* is slowing us down
--
- ... But what?
--
- The code doesn't have instrumentation
- Let's use state-of-the-art HTTP performance analysis!
<br/>(i.e. good old tools like `ab`, `httping`...)
---
## Accessing internal services
- `rng` and `hasher` are exposed on ports 8001 and 8002
- This is declared in the Compose file:
```yaml
...
rng:
build: rng
ports:
- "8001:80"
hasher:
build: hasher
ports:
- "8002:80"
...
```
---
## Measuring latency under load
We will use `httping`.
.exercise[
- Check the latency of `rng`:
```bash
httping -c 3 localhost:8001
```
- Check the latency of `hasher`:
```bash
httping -c 3 localhost:8002
```
]
`rng` has a much higher latency than `hasher`.
---
## Let's draw hasty conclusions
- The bottleneck seems to be `rng`
- *What if* we don't have enough entropy and can't generate enough random numbers?
- We need to scale out the `rng` service on multiple machines!
Note: this is a fiction! We have enough entropy. But we need a pretext to scale out.
(In fact, the code of `rng` uses `/dev/urandom`, which never runs out of entropy...
<br/>
...and is [just as good as `/dev/random`](http://www.slideshare.net/PacSecJP/filippo-plain-simple-reality-of-entropy).)
---
## Clean up
- Before moving on, let's remove those containers

14
slides/common/thankyou.md
View File

@@ -6,7 +6,7 @@ Thank you!
class: title, in-person
That's all folks! <br/> Questions?
That's all, folks! <br/> Questions?
![end](images/end.jpg)
@@ -14,13 +14,9 @@ That's all folks! <br/> Questions?
# Links and resources
- [Docker Community Slack](https://community.docker.com/registrations/groups/4316)
- [Docker Community Forums](https://forums.docker.com/)
- [Docker Hub](https://hub.docker.com)
- [Docker Blog](http://blog.docker.com/)
- [Docker documentation](http://docs.docker.com/)
- [Docker on StackOverflow](https://stackoverflow.com/questions/tagged/docker)
- [Docker on Twitter](http://twitter.com/docker)
- [Play With Docker Hands-On Labs](http://training.play-with-docker.com/)
- [Kubernetes Community](https://kubernetes.io/community/) - Slack, Google Groups, meetups
- [Play With Kubernetes Hands-On Labs](https://medium.com/@marcosnils/introducing-pwk-play-with-k8s-159fcfeb787b)
- [Local meetups](https://www.meetup.com/)
- [Microsoft Cloud Developer Advocates](https://developer.microsoft.com/en-us/advocates/)
.footnote[These slides (and future updates) are on → http://container.training/]

4
slides/common/title.md
View File

@@ -17,5 +17,5 @@ class: title, in-person
*Don't stream videos or download big files during the workshop.*<br/>
*Thank you!*
**Slides: http://container.training/**
]
**Slides: http://indexconf2018.container.training/**
]