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Docker Redis Introduction

	Docker-compose >>

Getting started with Docker Redis

Installing Docker (CentOS)

💻 Terminal

1. Install required packages
   # yum install -y yum-utils device-mapper-persistent-data lvm2
2. Set up the stable repository
   # yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
3. Install Docker
   # yum install docker-ce docker-ce-cli containerd.io

Starting Docker

💻 Terminal

1. Start Docker
   # systemctl start docker 
2. Enable Docker to start automatically on reboot
   # systemctl enable docker
3. Check Docker status
   # systemctl status docker

Checking the Docker version

💻 Terminal

# docker version
Client:
 Version:           18.09.2
 API version:       1.39
 Go version:        go1.10.6
 Git commit:        6247962
 Built:             Sun Feb 10 04:13:27 2019
 OS/Arch:           linux/amd64
 Experimental:      false

Server: Docker Engine - Community
 Engine:
  Version:          18.09.2
  API version:      1.39 (minimum version 1.12)
  Go version:       go1.10.6
  Git commit:       6247962
  Built:            Sun Feb 10 03:47:25 2019
  OS/Arch:          linux/amd64
  Experimental:     false

Pulling the latest Redis image

💻 Terminal

# docker pull redis
Using default tag: latest
...
Status: Downloaded newer image for docker.io/redis:latest

Pulling a Redis image with a specific version

💻 Terminal

# docker pull redis:5.0.3
5.0.3: Pulling from library/redis
...
Status: Downloaded newer image for docker.io/redis:5.0.3

Checking Redis images

💻 Terminal

# docker images
REPOSITORY   TAG      IMAGE ID       CREATED     SIZE
redis        5.0.3    0f55cf3661e9   9 days ago  95MB
redis        latest   0f55cf3661e9   9 days ago  95MB

Running a Redis server

💻 Terminal

# docker run --name myredis -p 6379:6379 -d redis:5.0.3

-d: run in the background

Connecting with redis-cli from Docker

💻 Terminal

# docker exec -it myredis redis-cli -p 6379
redis:6379> set key value
OK
redis:6379> get key
"value"
redis:6379> exit

Connecting with redis-cli on the host: use the mapped port 6379.

💻 Terminal

# redis-cli -p 6379
127.0.0.1:6379> keys *
1) "key"
127.0.0.1:6379> get key
"value"
127.0.0.1:6379> exit

Connecting to the Docker Linux shell

💻 Terminal

[redis ~]# docker ps
CONTAINER ID   IMAGE  COMMAND                 CREATED        STATUS        PORTS                   NAMES
ec2b694449eb   redis  "docker-entrypoint..."  9 minutes ago  Up 9 minutes  0.0.0.0:6379->6379/tcp  myredis   
[redis ~]# docker exec -it myredis /bin/bash
ec2b694449eb:/data# 
ec2b694449eb:/data# ls -l /usr/local/bin 		-> executable location
-rwxr-xr-x 1 root root  6802360 Dec  8 20:11 redis-benchmark
lrwxrwxrwx 1 root root       12 Dec  8 20:11 redis-check-aof -> redis-server
lrwxrwxrwx 1 root root       12 Dec  8 20:11 redis-check-rdb -> redis-server
-rwxr-xr-x 1 root root  7077984 Dec  8 20:11 redis-cli
lrwxrwxrwx 1 root root       12 Dec  8 20:11 redis-sentinel -> redis-server
-rwxr-xr-x 1 root root 15875624 Dec  8 20:11 redis-server
ec2b694449eb:/data# redis-cli -p 6379 		-> connect with redis-cli
127.0.0.1:6379>

redis.conf for Docker

Create the file /root/docker/redis-5.0.3/6001/redis.conf.
redis.conf example

📄 redis.conf

daemonize no
# bind 127.0.0.1
protected-mode no
port 6001
logfile "redis.log"
dir /data
cluster-announce-ip 192.168.10.10
cluster-announce-port 6001

If you set daemonize yes, it will not start.
Set protected-mode no, and comment out bind.
Specify the working dir. Use "/data", a directory inside the Docker image.
When installing as Redis Cluster: specify cluster-announce-ip and port. If you do not specify cluster-announce-ip, CLUSTER NODES may show a different IP.

Run with a specified redis.conf file: specify a volume

💻 Terminal

# docker run -v ./6001:/data --name myredis -p 6001:6001 -d redis redis-server /data/redis.conf

Docker commands

docker version: show the Docker version
netstat -tnlp: check ports and processes
Uninstall old versions: remove previous versions

💻 Terminal

# yum remove docker \
                  docker-client \
                  docker-client-latest \
                  docker-common \
                  docker-latest \
                  docker-latest-logrotate \
                  docker-logrotate \
                  docker-engine

docker info: show Docker information

💻 Terminal

Containers: 12
 Running: 12
 Paused: 0
 Stopped: 0
Images: 14
Server Version: 1.13.1
Storage Driver: overlay2
 Backing Filesystem: xfs
 Supports d_type: true
 Native Overlay Diff: true
Logging Driver: journald
Cgroup Driver: systemd
Plugins: 
 Volume: local
 Network: bridge host macvlan null overlay
Swarm: inactive
Runtimes: runc docker-runc
Default Runtime: docker-runc
Init Binary: /usr/libexec/docker/docker-init-current
containerd version:  (expected: aa8187dbd3b7ad67d8e5e3a15115d3eef43a7ed1)
runc version: N/A (expected: 9df8b306d01f59d3a8029be411de015b7304dd8f)
init version: fec3683b971d9c3ef73f284f176672c44b448662 (expected: 949e6facb77383876aeff8a6944dde66b3089574)
Security Options:
 seccomp
  WARNING: You're not using the default seccomp profile
  Profile: /etc/docker/seccomp.json
Kernel Version: 3.10.0-862.3.2.el7.x86_64
Operating System: CentOS Linux 7 (Core)
OSType: linux
Architecture: x86_64
Number of Docker Hooks: 3
CPUs: 8
Total Memory: 7.755 GiB
Name: localhost.localdomain
ID: HPDO:JAWX:G3DP:4QBX:EFCX:5BEX:THXT:L2H6:W3UO:K6UV:3I72:IUID
Docker Root Dir: /var/lib/docker
Debug Mode (client): false
Debug Mode (server): false
Registry: https://index.docker.io/v1/
Experimental: false
Insecure Registries:
 127.0.0.0/8
Live Restore Enabled: false
Registries: docker.io (secure)

docker run: run a container
docker run [OPTIONS] IMAGE [COMMAND] [ARG...]

💻 Terminal

docker run --name myredis -d -p 6379:6379 redis

docker ps: list containers
docker ps [OPTIONS]
When network_mode: host is used, PORTS is not shown.

💻 Terminal

CONTAINER ID   IMAGE                   COMMAND                  CREATED      STATUS      NAMES
01a59cca5082   redisgate/redis:5.0.3   "redis-server /red..."   6 hours ago  Up 6 hours  redis7001
91b5beb45389   redisgate/redis:5.0.3   "redis-server /red..."   6 hours ago  Up 6 hours  redis6002
61beb68f79f9   redisgate/redis:5.0.3   "redis-server /red..."   6 hours ago  Up 6 hours  redis7003

-a, --all: list all containers, including stopped ones.
-q, --quiet: show only container IDs.
Used like this: docker stop $(docker ps -q)

💻 Terminal

# docker ps -q
01a59cca5082
91b5beb45389
61beb68f79f9

-l, --latest: show the most recently created container.
-n, --last: show the n most recently created containers.

💻 Terminal

# docker ps -n=3
CONTAINER ID  IMAGE                  COMMAND                 CREATED      STATUS        NAMES
01a59cca5082  redisgate/redis:5.0.3  "redis-server /red..."  7 hours ago  Up 5 minutes  redis7001
91b5beb45389  redisgate/redis:5.0.3  "redis-server /red..."  7 hours ago  Up 5 minutes  redis6002
61beb68f79f9  redisgate/redis:5.0.3  "redis-server /red..."  7 hours ago  Up 5 minutes  redis7003

-s, --size: also show container size.

💻 Terminal

CONTAINER ID  IMAGE                   COMMAND                 CREATED      STATUS        NAMES      SIZE
01a59cca5082  redisgate/redis:5.0.3   "redis-server /red..."  7 hours ago  Up 8 minutes  redis7001  2 B (virtual 233 MB)
91b5beb45389  redisgate/redis:5.0.3   "redis-server /red..."  7 hours ago  Up 8 minutes  redis6002  2 B (virtual 233 MB)
61beb68f79f9  redisgate/redis:5.0.3   "redis-server /red..."  7 hours ago  Up 8 minutes  redis7003  2 B (virtual 233 MB)

-f, --filter: filter the containers shown.
Labels are specified in the docker-compose.yml file.

💻 Terminal

docker ps -f name=redis7001
docker ps -f status=created/restarting/running/removing/paused/exited/dead
docker ps -f network=bridge/host/none
docker ps -f label=redis/standalone/sentinel/cluster

--format: show selected fields.
docker ps -a --format "{{.Names}}: {{.Image}} {{.Networks}} Status={{.Status}}"| sort

💻 Terminal

redis6001: redisgate/redis:5.0.3 net=host Status=Up 19 minutes
redis6002: redisgate/redis:5.0.3 net=host Status=Up 19 minutes
redis7001: redisgate/redis:5.0.3 net=host Status=Up 19 minutes
redis7002: redisgate/redis:5.0.3 net=host Status=Up 19 minutes
redis7003: redisgate/redis:5.0.3 net=host Status=Up 19 minutes
sentinel16001: redisgate/redis:5.0.3 net=host Status=Up 19 minutes
sentinel16002: redisgate/redis:5.0.3 net=host Status=Up 19 minutes
sentinel16003: redisgate/redis:5.0.3 net=host Status=Exited (0) 14 seconds ago

docker logs: show container logs.
docker logs [OPTIONS] CONTAINER

docker logs redis6001
docker logs -f redis6001 -> same as tail -f
docker logs -t redis6001 -> show timestamps
journalctl -f -u docker.service -> available on CentOS.

docker inspect: show container and image details.
docker inspect [OPTIONS] NAME|ID [NAME|ID...]
docker top: show container process information.
docker top CONTAINER

💻 Terminal

# docker top redis6001
UID   PID    PPID   C  STIME  TTY  TIME      CMD
root  26100  26072  0  19:59  ?    00:00:07  redis-server *:6001

docker kill: kill a container.
docker kill [OPTIONS] CONTAINER [CONTAINER...]
docker cp: copy files from the container filesystem to the host OS filesystem, or copy host OS files into the container filesystem.
docker cp [OPTIONS] CONTAINER:SRC_PATH DEST_PATH
docker cp [OPTIONS] SRC_PATH CONTAINER:DEST_PATH

💻 Terminal

# docker cp redis6002:/redis/redis.log .
# docker cp ./a.txt redis6002:/redis

docker port: show mapped port information.
docker port CONTAINER [PRIVATE_PORT[/PROTO]]
Not shown when network_mode=host.
docker restart: restart a container.
docker restart [OPTIONS] CONTAINER [CONTAINER...]
docker stop: stop a container.
docker stop [OPTIONS] CONTAINER [CONTAINER...]
docker start: start a container.
docker start [OPTIONS] CONTAINER [CONTAINER...]
docker stats: continuously update and show container usage, like the Linux top command.
docker stats [OPTIONS] [CONTAINER...]
docker stats: in this case IDs are shown, so it is hard to tell which container is which.

💻 Terminal

CONTAINER       CPU %     MEM USAGE / LIMIT       MEM %      NET I/O      BLOCK I/O           PIDS
226b9f691af4    0.14%     1.75 MiB / 7.755 GiB    0.02%      0 B / 0 B    0 B / 19.5 kB       4
92b4917e2dba    0.21%     1.297 MiB / 7.755 GiB   0.02%      0 B / 0 B    0 B / 0 B           4
dae3dd368666    0.14%     1.734 MiB / 7.755 GiB   0.02%      0 B / 0 B    0 B / 16.9 kB       4
df1d85061157    0.15%     1.625 MiB / 7.755 GiB   0.02%      0 B / 0 B    0 B / 0 B           4

docker stats redis6001 redis6002

💻 Terminal

CONTAINER     CPU %      MEM USAGE / LIMIT       MEM %     NET I/O    BLOCK I/O         PIDS
redis6001     0.14%      1.75 MiB / 7.755 GiB    0.02%     0 B / 0 B  0 B / 19.5 kB     4
redis6002     0.21%      1.297 MiB / 7.755 GiB   0.02%     0 B / 0 B  0 B / 0 B         4

docker stats $(docker ps -a --format "{{.Names}}" | sort)

💻 Terminal

CONTAINER       CPU %     MEM USAGE / LIMIT       MEM %    NET I/O     BLOCK I/O           PIDS
redis6001       0.09%     1.621 MiB / 7.755 GiB   0.02%    0 B / 0 B   0 B / 24.6 kB       4
redis6002       0.07%     2.777 MiB / 7.755 GiB   0.03%    0 B / 0 B   0 B / 0 B           4
redis7001       0.12%     1.637 MiB / 7.755 GiB   0.02%    0 B / 0 B   0 B / 0 B           4
redis7002       0.12%     1.629 MiB / 7.755 GiB   0.02%    0 B / 0 B   0 B / 0 B           4
redis7003       0.12%     1.629 MiB / 7.755 GiB   0.02%    0 B / 0 B   0 B / 0 B           4
sentinel16001   0.14%     1.293 MiB / 7.755 GiB   0.02%    0 B / 0 B   0 B / 0 B           4
sentinel16002   0.12%     1.301 MiB / 7.755 GiB   0.02%    0 B / 0 B   0 B / 0 B           4
sentinel16003   --        -- / --                 --       --          --                  --

docker rename: rename a container.
docker rename CONTAINER NEW_NAME
docker pause: pause (suspend/freeze) a container. This uses the cgroups freezer. When paused, process state and contents are preserved, but CPU scheduling does not run. docker ps shows Status as Paused, and stats shows CPU usage as 0.00%.
docker pause CONTAINER [CONTAINER...]
docker unpause: unpause (unsuspend/unfreeze) a paused container.
docker unpause CONTAINER [CONTAINER...]
docker rm: remove a container.
docker rm [OPTIONS] CONTAINER [CONTAINER...]
docker rm $(docker ps -a -q --filter 'exited!=0')
docker save: save an image as a tar file.
docker save [OPTIONS] IMAGE [IMAGE...]
docker save -o redis2.tar redisgate/redis:5.0.3
docker load: load a tar file into the image store.
docker load [OPTIONS]
docker load -i redis2.tar

Other useful commands

Connect to a container shell
docker exec -it redis6001 /bin/bash
Check ports
netstat -tnlp
lsof -i -nP | grep LISTEN | awk '{print $(NF-1)" "$1}' | sort -u
View port forwarding information when Network_mode=bridge
iptables -t nat -L -n
Port forwarding settings when Network_mode=bridge

[root]# cat /proc/sys/net/ipv4/ip_forward
0
[root]# sysctl -w net.ipv4.ip_forward=1 set
net.ipv4.ip_forward = 1
[root]# cat /proc/sys/net/ipv4/ip_forward verify
1

Edit sysctl.conf so the changed value still applies after reboot.

[root]# vi /etc/sysctl.conf
net.ipv4.ip_forward = 1

You do not need to forward each port individually with firewall-cmd.

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