Docker - from development to production (PHPNW 2017-09-05)

DOCKER
FOR DEVELOPMENT
…
https://joind.in/talk/51971

Toby Griffiths
@ToG
Cubic Mushroom Ltd.

Docker - From development to production
A BRIEF HISTORY OF ME
‣ PHP Developer since early 2000s
‣ Self-employed web developer since 2011
‣ Contracted for various companies
‣ Experienced problems of inconsistent development/
production environments
‣ Some server conﬁguration knowledge
‣ Using Docker for 12+ months

‣ What is Docker?
‣ Docker for development
‣ Basic commands
‣ Running & linking multiple  
containers
‣ Customising images
‣ Gotchas
‣ Security considerations
WHAT I’LL COVER

Docker… it’s like virtual
machines, right?
Me, when I first discovered Docker

ADVANTAGES OF DOCKER OVER REGULAR VMS
▸ Smaller in size
▸ Don’t require a fully functional OS
▸ Can share read only ﬁle systems between containers
▸ Start up time
▸ Scalability
▸ Reduced resource requirements
▸ Can run 1000s of containers on a single host
▸ Reduced hardware requirements

WE ALREADY HAVE
SYSTEM THAT WORKS
WHY DOCKER?

DOCKER FOR DEVELOPMENT
▸ Consistent environments
▸ (Almost) No more "works for me" problems
▸ Ease of setup*
▸ Easier upgrades
▸ Easier to develop and test distributed services
▸ Causes better designed architecture
* Unless you’re using Windows

Docker - From Development to Production
DOCKER FOR PRODUCTION
▸ Consistent environments
▸ (Almost) No more "works for me" problems
▸ Better resource management
▸ Scalability
▸ Faster spin-up times

It does solve a lot of
problems, if you are facing
them
@dennisdegreef

// List images
$ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
busybox latest d20ae45477cb 10 days ago 1.13MB
CONTAINER IMAGES
// Pulling images
$ docker pull busybox
// Remove an image
$ docker rmi busybox

// Pulling and running
// If image is not found locally it will be pulled from registry
$ docker run --rm busybox:1.27.2 echo "Hello world"
RUNNING CONTAINERS
// Locally stored containers
$ docker run --name my-busybox busybox:latest echo "Hello world"
// Automatically removing containers when they stop
$ docker run --rm busybox:latest echo "Hello world"

// Include stopped containers
$ docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
636b77baa5c3 busybox "echo 'Hello world'" 1 second ago Exited (0) 4 seconds ago stoic_edison
fe68dac5f99c busybox "echo 'Hello world'" 3 seconds ago Exited (0) 5 seconds ago lucid_newton
171131c6a82d busybox "echo 'Hello world'" 4 seconds ago Exited (0) 8 seconds ago admiring_mirzakhani
8cbfcf2b2f32 nginx:latest "nginx -g 'daemon ..." 19 hours ago Up 19 hours 0.0.0.0:80->80/tcp, 443/tcp dockertalk_nginx_1
587849ab38e9 dockertalk_php "docker-php-entryp..." 19 hours ago Up 19 hours 9000/tcp dockertalk_php_1
1a8dbfc874a6 mysql:5.7 "docker-entrypoint..." 19 hours ago Up 19 hours 3306/tcp dockertalk_mysql_1
VIEWING CONTAINERS
// Running containers
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
8cbfcf2b2f32 nginx:latest "nginx -g 'daemon ..." 19 hours ago Up 19 hours 0.0.0.0:80->80/tcp, 443/tcp dockertalk_nginx_1
587849ab38e9 dockertalk_php "docker-php-entryp..." 19 hours ago Up 19 hours 9000/tcp dockertalk_php_1
1a8dbfc874a6 mysql:5.7 "docker-entrypoint..." 19 hours ago Up 19 hours 3306/tcp dockertalk_mysql_1

CONTAINERS THAT WON'T QUIT
// Run continuous containers
$ docker run --name my-nginx nginx:latest

CONTAINERS THAT WON'T QUIT
// Run continuous containers in the background
$ docker run --name my-nginx -d nginx:latest
$ docker ps --format
"table {{.ID}}t{{.Image}}t{{.Names}}t{{.Status}}"

RUNNING SHELLS INSIDE CONTAINERS
// Interactive shell
$ docker run --rm -it --name my-busybox-shell
busybox:latest sh
Docker ﬂags used here…
-t : Allocate a pseudo-tty
-i : Keep STDIN open even if not attached

// Run continuous container in the background
$ docker run --rm --name my-nginx -d nginx:latest
$ docker ps
STOPPING AND REMOVING CONTAINERS

// Stop a container
$ docker stop my-nginx

// Run continuous container in the background
$ docker run --name my-nginx -d nginx:latest
$ docker ps
// Kill a container
$ docker kill my-nginx

// Removed stopped container
$ docker ps -a
$ docker rm my-nginx
$ docker ps -a

FROM php:7.1-cl
VOLUME /var/www/html
# … or, using JSON notation, (so use double, not single quotes)…
VOLUME ["/var/www/html", "/var/log"]
WORKDIR /var/www/html
# Add content of files to /var/www/html
ADD ./files /var/www/html
# Add content of files to /var/www/html/files
ADD ./files /var/www/html/
# Add a remote download file
ADD http://example.com/foobar /var/www/html
# Add and decompress a LOCAL archive file
ADD ./files/archive.tar.gz /var/www/html
# Copy file without decompressing
COPY ./files/archive.tar.gz /var/www/html
CONFIGURE USING DOCKERFILES

FROM php:7.1-cl
# ...
ARG DEPLOY_STAGE
ARG DEPLOY_ENV=test
ENV SYMFONY_ENV=dev
EXPOSE 9000
USER www-data
GROUP www-data
ONBUILD RUN composer install
LABEL multi.label1="value1"
CONFIGURE USING DOCKERFILES

// Pass in build arguments to Dockerfile in the current
// directory
$ docker build
--build-arg MYSQL_ROOT_PASSWORD=my-secret-pw
.
CONFIGURE DURING BUILD USING BUILD ARGUMENTS

// Pass in environment variables
$ docker run --rm --name my-mysql
-e MYSQL_ROOT_PASSWORD=my-secret-pw
-d mysql:5.7
CONFIGURE AT RUNTIME USING ENVIRONMENT VARIABLES
// Pass in environment variables
$ docker run --rm --name my-mysql
--env-file /my/dirty/secrets
-d mysql:5.7

USING VOLUMES
// Mapping volumes
$ docker run --rm busybox:latest ls -als /usr
$ docker run --rm -v "$PWD/files:/usr/files" busybox:latest ls -als /usr
$ docker run --rm -v "$PWD/files:/usr/files" busybox:latest ls -als /usr/files

USING VOLUMES - OVERWRITING DIRECTORIES
// Overwriting directories
$ docker run --rm -v "$PWD/files:/usr" busybox:latest ls -als /usr

USING VOLUMES - NAMED VOLUMES
// Named volumes
$ docker run --rm -v named_volume:/usr busybox:latest ls -als /usr
$ docker run --rm -v named_volume:/named busybox:latest ls -als /named

// Inspect images
$ docker inspect busybox:latest | jq
INSPECTING IMAGES, CONTAINERS AND MORE

VIEWING CONTAINER LOGS
// View logs
$ docker logs my-mysql
// Follow logs
$ docker logs -f my-mysql

LINKING CONTAINERS
$ docker run --rm --name my-nginx -d nginx:latest
$ docker ps --format "table {{.ID}}t{{.Image}}t{{.Names}}t{{.Status}}"
$ docker run --rm busybox ping my-nginx

LINKING CONTAINERS
$ docker network create phpnw
$ docker inspect -f "{{json .Containers}}" phpnw | jq
$ docker network connect phpnw my-nginx
$ docker inspect -f "{{json .Containers}}" phpnw | jq

LINKING CONTAINERS
// Ping container from another
$ docker run --rm --network phpnw busybox
ping -c 4 my-nginx

// Demo sleep container
$ docker run --rm --name dont-restart-me -d busybox sleep 3
$ docker ps -a --format "table {{.ID}}t{{.Image}}t{{.Names}}t{{.Status}}"
// Always restart container
$ docker run --name restart-me -d --restart=always busybox sleep 3
KEEPING CONTAINERS RUNNING

KEEPING CONTAINERS RUNNING - INSPECTING DETAILS
// Viewing the restart count
$ docker inspect -f "{{ .RestartCount }}" restart-me
$ docker inspect -f "{{ .State.StartedAt }}" restart-me
// Stop & remove container
$ docker stop restart-me
$ docker rm restart-me

RESTART OPTIONS
Restart options…
no : (Default) Do not restart container when it
exits.
on-failure[:max-retries] : Restart only if the container
exits with a non-zero exit status.
Optionally, limit the number of restart
retries the Docker daemon attempts.
always : Always restart the container regardless of
the exit status.
Daemon will try to restart the container
indefinitely.
Will also always start on daemon startup.
unless-stopped : Always restart the container regardless of
the exit status, but do not start it on
daemon startup if the container has been
put to a stopped state before.

ACCESSING CONTAINERS FROM THE OUTSIDE WORLD
// Launch container
$ docker run --rm --name my-mysql -e MYSQL_ROOT_PASSWORD=my-secret-pw -d mysql:5.7
$ docker ps --format "table {{.ID}}t{{.Image}}t{{.Status}}t{{.Ports}}"
$ docker stop my-mysql

ACCESSING CONTAINERS FROM THE OUTSIDE WORLD
$ docker run --rm --name my-mysql --env-file /my/dirty/secrets -d -P mysql:5.7
$ docker run --rm --name my-mysql2 --env-file /my/dirty/secrets -d -p 80:80 mysql:5.7

NETWORK OPTIONS
The following ﬂags are available for controlling network settings for containers…
--dns=[] : Set custom DNS servers for the container
--network="bridge" : Connect a container to a network
Options
- 'bridge' : create a network stack on the default Docker
bridge
- 'none' : no networking
- 'container:<name|id>' : reuse another container's network
stack
- 'host' : use the Docker host network stack
- '<network-name>|<network-id>': connect to a user-defined
network
--network-alias=[] : Add network-scoped alias for the container
--add-host="" : Add a line to /etc/hosts (host:IP)
--mac-address="" : Sets the container's Ethernet device's MAC address
--ip="" : Sets the container's Ethernet device's IPv4 address
--ip6="" : Sets the container's Ethernet device's IPv6 address
--link-local-ip=[] : Sets one or more container's Ethernet device's
link local IPv4/IPv6 addresses

RESOURCES OPTIONS
The following ﬂags are available for controlling resource usage…
-m, --memory="" : Memory limit (format: <number>[<unit>]). Number is a positive integer. Unit can be
one of
b, k, m, or g. Minimum is 4M.
--memory-swap="" : Total memory limit (memory + swap, format: <number>[<unit>]). Number is a positive
integer. Unit can be one of b, k, m, or g.
--memory-reservation="" : Memory soft limit (format: <number>[<unit>]). Number is a positive integer. Unit can
be
one of b, k, m, or g.
--kernel-memory="" : Kernel memory limit (format: <number>[<unit>]). Number is a positive integer. Unit
can be
one of b, k, m, or g. Minimum is 4M.
-c, --cpu-shares=0 : CPU shares (relative weight)
--cpus=0.000 : Number of CPUs. Number is a fractional number. 0.000 means no limit.
--cpu-period=0 : Limit the CPU CFS (Completely Fair Scheduler) period
--cpuset-cpus="" : CPUs in which to allow execution (0-3, 0,1)
--cpuset-mems="" : Memory nodes (MEMs) in which to allow execution (0-3, 0,1). Only effective on NUMA
systems.
--cpu-quota=0 : Limit the CPU CFS (Completely Fair Scheduler) quota
--cpu-rt-period=0 : Limit the CPU real-time period. In microseconds. Requires parent cgroups be set and
cannot be higher than parent. Also check rtprio ulimits.
--cpu-rt-runtime=0 : Limit the CPU real-time runtime. In microseconds. Requires parent cgroups be set and
cannot be higher than parent. Also check rtprio ulimits.
--blkio-weight=0 : Block IO weight (relative weight) accepts a weight value between 10 and 1000.
… [and more options]

HELLO WORLD
(AND A LITTLE GOLANG FOR YOU)

HELLO WORLD
// hello-world.go
package main
import "fmt"
func main() {
fmt.Printf(
"Hello, PHP North Westn”
)
}
$ docker run --rm
-v "$PWD/files":/go
golang go run hello-world.go

HELLO WORLD
// hello-world.go
package main
import "fmt"
func main() {
fmt.Printf(
"Hello, PHP North Westn”
)
}
$ docker run --rm
-v "$PWD/files":/go
-e GOOS=darwin
golang go build hello-world.go
$ ./files/hello-world

AN NGINX WEB SERVER
// Expose container ports on defined host ports
$ docker run --rm --name my-nginx -d -p 80:80 nginx
$ docker ps

AN NGINX WEB SERVER - WITH FILES
// Expose container ports on defined
// host ports
$ docker run --rm --name my-nginx
-v "$PWD/files":/usr/share/nginx/html:ro
-p 80:80
-d
nginx
$ docker ps

<!doctype html>
<html lang="en">
<head>
<title>Hello, PHP North West!</title>
</head>
<body>
<h1>Hello, PHP North West!</h1>
</body>
</html>

DOCKER COMPOSE
version: '3'
services:
mysql:
image: mysql:5.7
environment:
MYSQL_ROOT_PASSWORD: root
MYSQL_DATABASE: phpnw
volumes:
- mysql_data:/var/lib/mysql:delegated
restart: unless-stopped
php:
build: ./files/docker/php/docker
volumes:
- web_files:/usr/share/nginx/html
depends_on:
- mysql

DOCKER COMPOSE - VOLUMES
version: '3'
services:
# ...
nginx:
image: nginx:latest
volumes:
- ./files/docker/nginx/conf/nginx.conf:/etc/nginx/nginx.conf:delegated
- ./files/docker/nginx/conf/conf.d/upstream.conf:/etc/nginx/conf.d/upstream.conf:delegated
- ./files/docker/nginx/conf/conf.d/default.dev.conf:/etc/nginx/conf.d/default.conf:delegated
- web_files:/usr/share/nginx/html
ports:
- 80:80
depends_on:
- php
volumes:
mysql_data: ~
# named volume mapped to host directory
web_files:
driver: local-persist # <<== uses local-persist plugin
driver_opts:
mountpoint: /path/on/host/machine/

DOCKER COMPOSE
$ docker-compose up

DOCKER COMPOSE
$ docker-compose up -d

DOCKER COMPOSE - LOGS
$ docker-compose logs -f

FROM php:7.1-apache
RUN apt-get update && apt-get install -y libfreetype6-dev libjpeg62-turbo-dev
libmcrypt-dev libpng12-dev
RUN docker-php-ext-install -j$(nproc) iconv mcrypt
RUN docker-php-ext-configure gd --with-freetype-dir=/usr/include/
--with-jpeg-dir=/usr/include/
RUN docker-php-ext-install -j$(nproc) gd
RUN docker-php-source delete
FROM php:7.1-apache
&& docker-php-ext-install -j$(nproc) iconv mcrypt
&& docker-php-ext-configure gd --with-freetype-dir=/usr/include/
&& docker-php-ext-install -j$(nproc) gd
&& docker-php-source delete
DOCKERFILES - A NOTE ABOUT IMAGE SIZES
VS

FROM php:7.1-apache
RUN docker-php-ext-install -j$(nproc) iconv mcrypt
RUN docker-php-ext-configure gd --with-freetype-dir=/usr/include/
RUN docker-php-ext-install -j$(nproc) gd
RUN docker-php-source delete
5 x RUN commands = 5 x image layers

FROM php:7.1-apache
&& docker-php-ext-install -j$(nproc) iconv mcrypt
&& docker-php-ext-configure gd --with-freetype-dir=/usr/include/
&& docker-php-ext-install -j$(nproc) gd
&& docker-php-source delete
1 x RUN commands = 1 x image layers

FILESYSTEM LIMITATIONS
‣ File name length limit
‣ Limit of 242 characters (rather than 255)
‣ Symfony/Doctrine cache ﬁles
‣ Prepare cache inside the container

‣ Docker for Mac
‣ Performance issues
‣ Use :cached or :delegated sufﬁx on volume
declarations, to allow delayed updates… 
 
$ docker run -v "$PWD:/home:cached" php:7.1-cli 
$ docker run -v "$PWD:/home:delegated" php:7.1-cli

‣ File permissions on volumes differ between hosts types
‣ On Docker for Mac the permissions are kept to those of
the running user
‣ On Docker for Linux the permissions on the host match
the user:group IDs set within the container
‣ Window???

SECURITY CONSIDERATIONS
‣ Kernel exploits
‣ Kernel panics within container will bring down the host machine
‣ Denial of Service
‣ Containers can hog host resources
‣ Image trustworthiness
‣ Secrets
‣ Conﬁdential information can be stored into Docker images (e.g. in
--build-args), if not careful

SECURITY CONSIDERATIONS
‣ Patching core packages
‣ Run system updates within container?
‣ Update packages on image build, and re-build regularly
‣ Container breakout
‣ User permissions in the container = user permissions
outside
‣ Namespace users (see http://dockr.ly/2wEfy2g)

The End!
Toby Griffiths
@ToG
Cubic Mushroom Ltd.
https://joind.in/talk/51971

Docker - from development to production (PHPNW 2017-09-05)

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