1. docker
  2. Commit 920cb5834b66a27b68b83c5b4e81f027103ced68
Browse code

Merge pull request #26706 from thaJeztah/update-systemd-instructions

Cleanup / sync RHEL, CentOS, Fedora installation docs

Sebastiaan van Stijn authored on 2016/09/20 05:10:30
Showing 3 changed files
docs/installation/linux/centos.md
History View file @ 920cb58
... ... 
@@ -16,114 +16,151 @@ Docker runs on CentOS 7.X. An installation on other binary compatible EL7
16 16 
 distributions such as Scientific Linux might succeed, but Docker does not test
17 17 
 or support Docker on these distributions.
18 18
19 
-This page instructs you to install using Docker-managed release packages and
20 
-installation mechanisms. Using these packages ensures you get the latest release
21 
-of Docker. If you wish to install using CentOS-managed packages, consult your
22 
-CentOS documentation.
19 
+These instructions install Docker using release packages and installation
20 
+mechanisms managed by Docker, to be sure that you get the latest version
21 
+of Docker. If you wish to install using CentOS-managed packages, consult
22 
+your CentOS release documentation.
23 23
24 24 
 ## Prerequisites
25 25
26 
-Docker requires a 64-bit installation regardless of your CentOS version. Also,
27 
-your kernel must be 3.10 at minimum, which CentOS 7 runs.
26 
+Docker requires a 64-bit OS and version 3.10 or higher of the Linux kernel.
28 27
29 28 
 To check your current kernel version, open a terminal and use `uname -r` to
30 29 
 display your kernel version:
31 30
32 
-    $ uname -r
33 
-    3.10.0-229.el7.x86_64
31 
+```bash
32 
+$ uname -r
33 
+3.10.0-229.el7.x86_64
34 
+```
34 35
35 
-Finally, it is recommended that you fully update your system. Please keep in
36 
-mind that your system should be fully patched to fix any potential kernel bugs.
36 
+Finally, it is recommended that you fully update your system. Keep in mind
37 
+that your system should be fully patched to fix any potential kernel bugs.
37 38 
 Any reported kernel bugs may have already been fixed on the latest kernel
38 39 
 packages.
39 40
40 
-## Install
41 
+## Install Docker Engine
41 42
42 
-There are two ways to install Docker Engine.  You can install using the `yum`
43 
-package manager. Or you can use `curl` with the  `get.docker.com` site. This
44 
-second method runs an installation script which also installs via the `yum`
45 
-package manager.
43 
+There are two ways to install Docker Engine.  You can [install using the `yum`
44 
+package manager](#install-with-yum). Or you can use `curl` with the [`get.docker.com`
45 
+site](#install-with-the-script). This second method runs an installation script
46 
+which also installs via the `yum` package manager.
46 47
47 48 
 ### Install with yum
48 49
49 50 
 1. Log into your machine as a user with `sudo` or `root` privileges.
50 51
51 
-2. Make sure your existing yum packages are up-to-date.
52 
+2. Make sure your existing packages are up-to-date.
52 53
53 
-        $ sudo yum update
54 
+    ```bash
55 
+    $ sudo yum update
56 
+    ```
54 57
55 
-3. Add the yum repo.
58 
+3. Add the `yum` repo.
56 59
57 
-        $ sudo tee /etc/yum.repos.d/docker.repo <<-'EOF'
58 
-        [dockerrepo]
59 
-        name=Docker Repository
60 
-        baseurl=https://yum.dockerproject.org/repo/main/centos/7/
61 
-        enabled=1
62 
-        gpgcheck=1
63 
-        gpgkey=https://yum.dockerproject.org/gpg
64 
-        EOF
60 
+    ```bash
61 
+    $ sudo tee /etc/yum.repos.d/docker.repo <<-'EOF'
62 
+    [dockerrepo]
63 
+    name=Docker Repository
64 
+    baseurl=https://yum.dockerproject.org/repo/main/centos/7/
65 
+    enabled=1
66 
+    gpgcheck=1
67 
+    gpgkey=https://yum.dockerproject.org/gpg
68 
+    EOF
69 
+    ```
65 70
66 71 
 4. Install the Docker package.
67 72
68 
-        $ sudo yum install docker-engine
73 
+    ```bash
74 
+    $ sudo yum install docker-engine
75 
+    ```
69 76
70 
-5. Start the Docker daemon.
77 
+5. Enable the service.
71 78
72 
-        $ sudo service docker start
79 
+    ```bash
80 
+    $ sudo systemctl enable docker.service
81 
+    ```
73 82
74 
-6. Verify `docker` is installed correctly by running a test image in a container.
83 
+6. Start the Docker daemon.
84 
+
85 
+    ```bash
86 
+    $ sudo systemctl start docker
87 
+    ```
88 
+
89 
+7. Verify `docker` is installed correctly by running a test image in a container.
90 
+
91 
+        $ sudo docker run --rm hello-world
75 92
76 
-        $ sudo docker run hello-world
77 93 
         Unable to find image 'hello-world:latest' locally
78 
-    		latest: Pulling from hello-world
79 
-    		a8219747be10: Pull complete
80 
-    		91c95931e552: Already exists
81 
-    		hello-world:latest: The image you are pulling has been verified. Important: image verification is a tech preview feature and should not be relied on to provide security.
82 
-    		Digest: sha256:aa03e5d0d5553b4c3473e89c8619cf79df368babd1.7.1cf5daeb82aab55838d
83 
-    		Status: Downloaded newer image for hello-world:latest
84 
-    		Hello from Docker.
85 
-    		This message shows that your installation appears to be working correctly.
86 
-
87 
-    		To generate this message, Docker took the following steps:
88 
-    		 1. The Docker client contacted the Docker daemon.
89 
-    		 2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
90 
-    				(Assuming it was not already locally available.)
91 
-    		 3. The Docker daemon created a new container from that image which runs the
92 
-    				executable that produces the output you are currently reading.
93 
-    		 4. The Docker daemon streamed that output to the Docker client, which sent it
94 
-    				to your terminal.
95 
-
96 
-    		To try something more ambitious, you can run an Ubuntu container with:
97 
-    		 $ docker run -it ubuntu bash
98 
-
99 
-    		For more examples and ideas, visit:
100 
-    		 http://docs.docker.com/userguide/
94 
+        latest: Pulling from library/hello-world
95 
+        c04b14da8d14: Pull complete
96 
+        Digest: sha256:0256e8a36e2070f7bf2d0b0763dbabdd67798512411de4cdcf9431a1feb60fd9
97 
+        Status: Downloaded newer image for hello-world:latest
101 98
102 
-### Install with the script
99 
+        Hello from Docker!
100 
+        This message shows that your installation appears to be working correctly.
101 
+
102 
+        To generate this message, Docker took the following steps:
103 
+         1. The Docker client contacted the Docker daemon.
104 
+         2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
105 
+         3. The Docker daemon created a new container from that image which runs the
106 
+            executable that produces the output you are currently reading.
107 
+         4. The Docker daemon streamed that output to the Docker client, which sent it
108 
+            to your terminal.
109 
+
110 
+        To try something more ambitious, you can run an Ubuntu container with:
111 
+         $ docker run -it ubuntu bash
103 112
113 
+        Share images, automate workflows, and more with a free Docker Hub account:
114 
+         https://hub.docker.com
115 
+
116 
+        For more examples and ideas, visit:
117 
+         https://docs.docker.com/engine/userguide/
118 
+
119 
+If you need to add an HTTP Proxy, set a different directory or partition for the
120 
+Docker runtime files, or make other customizations, read our Systemd article to
121 
+learn how to [customize your Systemd Docker daemon options](../../admin/systemd.md).
122 
+
123 
+### Install with the script
104 124
105 125 
 1. Log into your machine as a user with `sudo` or `root` privileges.
106 126
107 
-2. Make sure your existing yum packages are up-to-date.
127 
+2. Make sure your existing packages are up-to-date.
108 128
109 
-		$ sudo yum update
129 
+    ```bash
130 
+    $ sudo yum update
131 
+    ```
110 132
111 133 
 3. Run the Docker installation script.
112 134
113 
-		$ curl -fsSL https://get.docker.com/ | sh
135 
+    ```bash
136 
+    $ curl -fsSL https://get.docker.com/ | sh
137 
+    ```
114 138
115 
-	This script adds the `docker.repo` repository and installs Docker.
139 
+    This script adds the `docker.repo` repository and installs Docker.
116 140
117 
-4. Start the Docker daemon.
141 
+4. Enable the service.
118 142
119 
-		$ sudo service docker start
143 
+    ```bash
144 
+    $ sudo systemctl enable docker.service
145 
+    ```
120 146
121 
-5. Verify `docker` is installed correctly by running a test image in a container.
147 
+5. Start the Docker daemon.
148 
+
149 
+    ```bash
150 
+    $ sudo systemctl start docker
151 
+    ```
152 
+
153 
+6. Verify `docker` is installed correctly by running a test image in a container.
122 154
123 
-		$ sudo docker run hello-world
155 
+    ```bash
156 
+    $ sudo docker run hello-world
157 
+    ```
124 158
159 
+If you need to add an HTTP Proxy, set a different directory or partition for the
160 
+Docker runtime files, or make other customizations, read our Systemd article to
161 
+learn how to [customize your Systemd Docker daemon options](../../admin/systemd.md).
125 162
126 
-## Create a docker group
163 
+## Create a docker group
127 164
128 165 
 The `docker` daemon binds to a Unix socket instead of a TCP port. By default
129 166 
 that Unix socket is owned by the user `root` and other users can access it with
... ... 
@@ -139,54 +176,63 @@ makes the ownership of the Unix socket read/writable by the `docker` group.
139 139
140 140 
 To create the `docker` group and add your user:
141 141
142 
-1. Log into Centos as a user with `sudo` privileges.
142 
+1. Log into your machine as a user with `sudo` or `root` privileges.
143 143
144 144 
 2. Create the `docker` group.
145 145
146 
-    `sudo groupadd docker`
146 
+    ```bash
147 
+    $ sudo groupadd docker
148 
+    ```
147 149
148 150 
 3. Add your user to `docker` group.
149 151
150 
-    `sudo usermod -aG docker your_username`
152 
+    ```bash
153 
+    $ sudo usermod -aG docker your_username`
154 
+    ```
151 155
152 156 
 4. Log out and log back in.
153 157
154 158 
     This ensures your user is running with the correct permissions.
155 159
156 
-5. Verify your work by running `docker` without `sudo`.
160 
+5. Verify that your user is in the docker group by running `docker` without `sudo`.
157 161
158 
-		$ docker run hello-world
162 
+    ```bash
163 
+    $ docker run hello-world
164 
+    ```
159 165
160 166 
 ## Start the docker daemon at boot
161 167
162 
-To ensure Docker starts when you boot your system, do the following:
163 
-
164 
-      $ sudo chkconfig docker on
165 
-
166 
-If you need to add an HTTP Proxy, set a different directory or partition for the
167 
-Docker runtime files, or make other customizations, read our Systemd article to
168 
-learn how to [customize your Systemd Docker daemon options](../../admin/systemd.md).
168 
+Configure the Docker daemon to start automatically when the host starts:
169 169
170 
+```bash
171 
+$ sudo systemctl enable docker
172 
+```
170 173
171 174 
 ## Uninstall
172 175
173 
-You can uninstall the Docker software with `yum`.
176 
+You can uninstall the Docker software with `yum`.
177 
+
178 
+1. List the installed Docker packages.
174 179
175 
-1. List the package you have installed.
180 
+    ```bash
181 
+    $ yum list installed | grep docker
176 182
177 
-		$ yum list installed | grep docker
178 
-		yum list installed | grep docker
179 
-		docker-engine.x86_64   1.7.1-1.el7 @/docker-engine-1.7.1-1.el7.x86_64.rpm
183 
+    docker-engine.x86_64     1.7.1-0.1.el7@/docker-engine-1.7.1-0.1.el7.x86_64
184 
+    ```
180 185
181 186 
 2. Remove the package.
182 187
183 
-		$ sudo yum -y remove docker-engine.x86_64
188 
+    ```bash
189 
+    $ sudo yum -y remove docker-engine.x86_64
190 
+    ```
184 191
185 192 
 	This command does not remove images, containers, volumes, or user-created
186 193 
 	configuration files on your host.
187 194
188 195 
 3. To delete all images, containers, and volumes, run the following command:
189 196
190 
-		$ rm -rf /var/lib/docker
197 
+    ```bash
198 
+    $ rm -rf /var/lib/docker
199 
+    ```
191 200
192 201 
 4. Locate and delete any user-created configuration files.
docs/installation/linux/fedora.md
History View file @ 920cb58
... ... 
@@ -12,80 +12,94 @@ weight=-3
12 12
13 13 
 # Fedora
14 14
15 
-Docker is supported on Fedora version 22, 23, and 24. This page instructs you to install
16 
-using Docker-managed release packages and installation mechanisms. Using these
17 
-packages ensures you get the latest release of Docker. If you wish to install
18 
-using Fedora-managed packages, consult your Fedora release documentation for
19 
-information on Fedora's Docker support.
15 
+Docker is supported on Fedora version 22, 23, and 24. These instructions install
16 
+Docker using release packages and installation mechanisms managed by Docker, to
17 
+be sure that you get the latest version of Docker. If you wish to install using
18 
+Fedora-managed packages, consult your Fedora release documentation.
20 19
21 20 
 ## Prerequisites
22 21
23 
-Docker requires a 64-bit installation regardless of your Fedora version. Also, your kernel must be 3.10 at minimum. To check your current kernel
24 
-version, open a terminal and use `uname -r` to display your kernel version:
22 
+Docker requires a 64-bit OS and version 3.10 or higher of the Linux kernel.
25 23
26 
-    $ uname -r
27 
-    3.19.5-100.fc21.x86_64
24 
+To check your current kernel version, open a terminal and use `uname -r` to
25 
+display your kernel version:
28 26
29 
-If your kernel is at an older version, you must update it.
27 
+```bash
28 
+$ uname -r
29 
+3.19.5-100.fc21.x86_64
30 
+```
30 31
31 
-Finally, is it recommended that you fully update your system. Please keep in
32 
-mind that your system should be fully patched to fix any potential kernel bugs. Any
33 
-reported kernel bugs may have already been fixed on the latest kernel packages
32 
+If your kernel is at an older version, you must update it.
34 33
34 
+Finally, it is recommended that you fully update your system. Keep in mind
35 
+that your system should be fully patched to fix any potential kernel bugs.
36 
+Any reported kernel bugs may have already been fixed on the latest kernel
37 
+packages.
35 38
36 
-## Install
39 
+## Install Docker Engine
37 40
38 
-There are two ways to install Docker Engine.  You can install with the `dnf` package manager. Or you can use `curl` with the  `get.docker.com` site. This second method runs an installation script which also installs via the `dnf` package manager.
41 
+There are two ways to install Docker Engine.  You can [install using the `dnf`
42 
+package manager](#install-with-dnf). Or you can use `curl` [with the  `get.docker.com`
43 
+site](#install-with-the-script). This second method runs an installation script
44 
+which also installs via the `dnf` package manager.
39 45
40 46 
 ### Install with DNF
41 47
42 48 
 1. Log into your machine as a user with `sudo` or `root` privileges.
43 49
44 
-2. Make sure your existing dnf packages are up-to-date.
50 
+2. Make sure your existing packages are up-to-date.
45 51
46 
-		$ sudo dnf update
52 
+    ```bash
53 
+    $ sudo dnf update
54 
+    ```
47 55
48 
-3. Add the yum repo yourself.
56 
+3. Add the `yum` repo.
49 57
50 
-        $ sudo tee /etc/yum.repos.d/docker.repo <<-'EOF'
51 
-        [dockerrepo]
52 
-        name=Docker Repository
53 
-        baseurl=https://yum.dockerproject.org/repo/main/fedora/$releasever/
54 
-        enabled=1
55 
-        gpgcheck=1
56 
-        gpgkey=https://yum.dockerproject.org/gpg
57 
-        EOF
58 
+    ```bash
59 
+    $ sudo tee /etc/yum.repos.d/docker.repo <<-'EOF'
60 
+    [dockerrepo]
61 
+    name=Docker Repository
62 
+    baseurl=https://yum.dockerproject.org/repo/main/fedora/$releasever/
63 
+    enabled=1
64 
+    gpgcheck=1
65 
+    gpgkey=https://yum.dockerproject.org/gpg
66 
+    EOF
67 
+    ```
58 68
59 69 
 4. Install the Docker package.
60 70
61 
-        $ sudo dnf install docker-engine
71 
+    ```bash
72 
+    $ sudo dnf install docker-engine
73 
+    ```
62 74
63 75 
 5. Enable the service.
64 76
65 
-		$ sudo systemctl enable docker.service
77 
+    ```bash
78 
+    $ sudo systemctl enable docker.service
79 
+    ```
66 80
67 81 
 6. Start the Docker daemon.
68 82
69 
-		$ sudo systemctl start docker
83 
+    ```bash
84 
+    $ sudo systemctl start docker
85 
+    ```
70 86
71 87 
 7. Verify `docker` is installed correctly by running a test image in a container.
72 88
89 
+        $ sudo docker run --rm hello-world
73 90
74 
-        $ sudo docker run hello-world
75 91 
         Unable to find image 'hello-world:latest' locally
76 
-        latest: Pulling from hello-world
77 
-        a8219747be10: Pull complete
78 
-        91c95931e552: Already exists
79 
-        hello-world:latest: The image you are pulling has been verified. Important: image verification is a tech preview feature and should not be relied on to provide security.
80 
-        Digest: sha256:aa03e5d0d5553b4c3473e89c8619cf79df368babd1.7.1cf5daeb82aab55838d
92 
+        latest: Pulling from library/hello-world
93 
+        c04b14da8d14: Pull complete
94 
+        Digest: sha256:0256e8a36e2070f7bf2d0b0763dbabdd67798512411de4cdcf9431a1feb60fd9
81 95 
         Status: Downloaded newer image for hello-world:latest
82 
-        Hello from Docker.
96 
+
97 
+        Hello from Docker!
83 98 
         This message shows that your installation appears to be working correctly.
84 99
85 100 
         To generate this message, Docker took the following steps:
86 101 
          1. The Docker client contacted the Docker daemon.
87 102 
          2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
88 
-            (Assuming it was not already locally available.)
89 103 
          3. The Docker daemon created a new container from that image which runs the
90 104 
             executable that produces the output you are currently reading.
91 105 
          4. The Docker daemon streamed that output to the Docker client, which sent it
... ... 
@@ -94,36 +108,57 @@ There are two ways to install Docker Engine.  You can install with the `dnf` pac
94 94 
         To try something more ambitious, you can run an Ubuntu container with:
95 95 
          $ docker run -it ubuntu bash
96 96
97 
+        Share images, automate workflows, and more with a free Docker Hub account:
98 
+         https://hub.docker.com
99 
+
97 100 
         For more examples and ideas, visit:
98 
-         http://docs.docker.com/userguide/
101 
+         https://docs.docker.com/engine/userguide/
99 102
103 
+If you need to add an HTTP Proxy, set a different directory or partition for the
104 
+Docker runtime files, or make other customizations, read our Systemd article to
105 
+learn how to [customize your Systemd Docker daemon options](../../admin/systemd.md).
100 106
101 107 
 ### Install with the script
102 108
109 
+You use the same installation procedure for all versions of Fedora.
103 110
104 111 
 1. Log into your machine as a user with `sudo` or `root` privileges.
105 112
106 
-2. Make sure your existing dnf packages are up-to-date.
113 
+2. Make sure your existing packages are up-to-date.
107 114
108 
-		$ sudo dnf update
115 
+    ```bash
116 
+    $ sudo dnf update
117 
+    ```
109 118
110 119 
 3. Run the Docker installation script.
111 120
112 
-		$ curl -fsSL https://get.docker.com/ | sh
121 
+    ```bash
122 
+    $ curl -fsSL https://get.docker.com/ | sh
123 
+    ```
113 124
114 
-	This script adds the `docker.repo` repository and installs Docker.
125 
+    This script adds the `docker.repo` repository and installs Docker.
115 126
116 127 
 4. Enable the service.
117 128
118 
-		$ sudo systemctl enable docker.service
129 
+    ```bash
130 
+    $ sudo systemctl enable docker.service
131 
+    ```
119 132
120 133 
 5. Start the Docker daemon.
121 134
122 
-        $ sudo systemctl start docker
135 
+    ```bash
136 
+    $ sudo systemctl start docker
137 
+    ```
123 138
124 139 
 6. Verify `docker` is installed correctly by running a test image in a container.
125 140
126 
-		$ sudo docker run hello-world
141 
+    ```bash
142 
+    $ sudo docker run hello-world
143 
+    ```
144 
+
145 
+If you need to add an HTTP Proxy, set a different directory or partition for the
146 
+Docker runtime files, or make other customizations, read our Systemd article to
147 
+learn how to [customize your Systemd Docker daemon options](../../admin/systemd.md).
127 148
128 149 
 ## Create a docker group
129 150
... ... 
@@ -141,27 +176,37 @@ makes the ownership of the Unix socket read/writable by the `docker` group.
141 141
142 142 
 To create the `docker` group and add your user:
143 143
144 
-1. Log into your system as a user with `sudo` privileges.
144 
+1. Log into your machine as a user with `sudo` or `root` privileges.
145 145
146 146 
 2. Create the `docker` group.
147 147
148 
-    `sudo groupadd docker`
148 
+    ```bash
149 
+    $ sudo groupadd docker
150 
+    ```
149 151
150 152 
 3. Add your user to `docker` group.
151 153
152 
-    `sudo usermod -aG docker your_username`
154 
+    ```bash
155 
+    $ sudo usermod -aG docker your_username`
156 
+    ```
153 157
154 158 
 4. Log out and log back in.
155 159
156 160 
     This ensures your user is running with the correct permissions.
157 161
158 
-5. Verify your work by running `docker` without `sudo`.
162 
+5. Verify that your user is in the docker group by running `docker` without `sudo`.
159 163
160 
-        $ docker run hello-world
164 
+    ```bash
165 
+    $ docker run hello-world
166 
+    ```
161 167
162 
-If you need to add an HTTP Proxy, set a different directory or partition for the
163 
-Docker runtime files, or make other customizations, read our Systemd article to
164 
-learn how to [customize your Systemd Docker daemon options](../../admin/systemd.md).
168 
+## Start the docker daemon at boot
169 
+
170 
+Configure the Docker daemon to start automatically when the host starts:
171 
+
172 
+```bash
173 
+$ sudo systemctl enable docker
174 
+```
165 175
166 176 
 ## Running Docker with a manually-defined network
167 177
... ... 
@@ -186,20 +231,27 @@ This configuration allows IP forwarding from the container as expected.
186 186
187 187 
 You can uninstall the Docker software with `dnf`.
188 188
189 
-1. List the package you have installed.
189 
+1. List the installed Docker packages.
190 
+
191 
+    ```bash
192 
+    $ dnf list installed | grep docker
190 193
191 
-		$ dnf list installed | grep docker
192 
-		docker-engine.x86_64     1.7.1-0.1.fc21 @/docker-engine-1.7.1-0.1.fc21.el7.x86_64
194 
+    docker-engine.x86_64     1.7.1-0.1.fc21 @/docker-engine-1.7.1-0.1.fc21.el7.x86_64
195 
+    ```
193 196
194 197 
 2. Remove the package.
195 198
196 
-		$ sudo dnf -y remove docker-engine.x86_64
199 
+    ```bash
200 
+    $ sudo dnf -y remove docker-engine.x86_64
201 
+    ```
197 202
198 203 
 	This command does not remove images, containers, volumes, or user-created
199 204 
 	configuration files on your host.
200 205
201 206 
 3. To delete all images, containers, and volumes, run the following command:
202 207
203 
-		$ rm -rf /var/lib/docker
208 
+    ```bash
209 
+    $ rm -rf /var/lib/docker
210 
+    ```
204 211
205 212 
 4. Locate and delete any user-created configuration files.
docs/installation/linux/rhel.md
History View file @ 920cb58
... ... 
@@ -12,110 +12,151 @@ weight = -5
12 12
13 13 
 # Red Hat Enterprise Linux
14 14
15 
-Docker is supported on Red Hat Enterprise Linux 7. This page instructs you to
16 
-install using Docker-managed release packages and installation mechanisms. Using
17 
-these packages ensures you get the latest release of Docker. If you wish to
18 
-install using Red Hat-managed packages, consult your Red Hat release
19 
-documentation for information on Red Hat's Docker support.
15 
+Docker is supported on Red Hat Enterprise Linux 7. These instructions install
16 
+Docker using release packages and installation mechanisms managed by Docker,
17 
+to be sure that you get the latest version of Docker. If you wish to install
18 
+using Red Hat-managed packages, consult your Red Hat release documentation.
20 19
21 20 
 ## Prerequisites
22 21
23 
-Docker requires a 64-bit installation regardless of your Red Hat version. Docker
24 
-requires that your kernel must be 3.10 at minimum, which Red Hat 7 runs.
22 
+Docker requires a 64-bit OS and version 3.10 or higher of the Linux kernel.
25 23
26 24 
 To check your current kernel version, open a terminal and use `uname -r` to
27 25 
 display your kernel version:
28 26
29 
-    $ uname -r
30 
-    3.10.0-229.el7.x86_64
27 
+```bash
28 
+$ uname -r
29 
+3.10.0-229.el7.x86_64
30 
+```
31 31
32 
-Finally, is it recommended that you fully update your system. Please keep in
33 
-mind that your system should be fully patched to fix any potential kernel bugs.
32 
+Finally, it is recommended that you fully update your system. Keep in mind
33 
+that your system should be fully patched to fix any potential kernel bugs.
34 34 
 Any reported kernel bugs may have already been fixed on the latest kernel
35 35 
 packages.
36 36
37 37 
 ## Install Docker Engine
38 38
39 
-There are two ways to install Docker Engine.  You can install with the `yum` package manager directly yourself. Or you can use `curl` with the  `get.docker.com` site. This second method runs an installation script which installs via the `yum` package manager.
39 
+There are two ways to install Docker Engine.  You can [install using the `yum`
40 
+package manager](#install-with-yum). Or you can use `curl` with the [`get.docker.com`
41 
+site](#install-with-the-script). This second method runs an installation script
42 
+which also installs via the `yum` package manager.
40 43
41 44 
 ### Install with yum
42 45
43 46 
 1. Log into your machine as a user with `sudo` or `root` privileges.
44 47
45 
-2. Make sure your existing yum packages are up-to-date.
48 
+2. Make sure your existing packages are up-to-date.
46 49
47 
-  		$ sudo yum update
50 
+    ```bash
51 
+    $ sudo yum update
52 
+    ```
48 53
49 
-3. Add the yum repo yourself.
54 
+3. Add the `yum` repo.
50 55
51 
-        $ sudo tee /etc/yum.repos.d/docker.repo <<-EOF
52 
-        [dockerrepo]
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-        name=Docker Repository
54 
-        baseurl=https://yum.dockerproject.org/repo/main/centos/7
55 
-        enabled=1
56 
-        gpgcheck=1
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-        gpgkey=https://yum.dockerproject.org/gpg
58 
-        EOF
56 
+    ```bash
57 
+    $ sudo tee /etc/yum.repos.d/docker.repo <<-'EOF'
58 
+    [dockerrepo]
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+    name=Docker Repository
60 
+    baseurl=https://yum.dockerproject.org/repo/main/centos/7/
61 
+    enabled=1
62 
+    gpgcheck=1
63 
+    gpgkey=https://yum.dockerproject.org/gpg
64 
+    EOF
65 
+    ```
59 66
60 67 
 4. Install the Docker package.
61 68
62 
-        $ sudo yum install docker-engine
69 
+    ```bash
70 
+    $ sudo yum install docker-engine
71 
+    ```
63 72
64 
-5. Start the Docker daemon.
73 
+5. Enable the service.
65 74
66 
-		$ sudo service docker start
75 
+    ```bash
76 
+    $ sudo systemctl enable docker.service
77 
+    ```
67 78
68 
-6. Verify `docker` is installed correctly by running a test image in a container.
79 
+6. Start the Docker daemon.
80 
+
81 
+    ```bash
82 
+    $ sudo systemctl start docker
83 
+    ```
84 
+
85 
+7. Verify `docker` is installed correctly by running a test image in a container.
86 
+
87 
+        $ sudo docker run --rm hello-world
69 88
70 
-		$ sudo docker run hello-world
71 89 
         Unable to find image 'hello-world:latest' locally
72 
-    		latest: Pulling from hello-world
73 
-    		a8219747be10: Pull complete
74 
-    		91c95931e552: Already exists
75 
-    		hello-world:latest: The image you are pulling has been verified. Important: image verification is a tech preview feature and should not be relied on to provide security.
76 
-    		Digest: sha256:aa03e5d0d5553b4c3473e89c8619cf79df368babd1.7.1cf5daeb82aab55838d
77 
-    		Status: Downloaded newer image for hello-world:latest
78 
-    		Hello from Docker.
79 
-    		This message shows that your installation appears to be working correctly.
80 
-
81 
-    		To generate this message, Docker took the following steps:
82 
-    		 1. The Docker client contacted the Docker daemon.
83 
-    		 2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
84 
-    				(Assuming it was not already locally available.)
85 
-    		 3. The Docker daemon created a new container from that image which runs the
86 
-    				executable that produces the output you are currently reading.
87 
-    		 4. The Docker daemon streamed that output to the Docker client, which sent it
88 
-    				to your terminal.
89 
-
90 
-    		To try something more ambitious, you can run an Ubuntu container with:
91 
-    		 $ docker run -it ubuntu bash
92 
-
93 
-    		For more examples and ideas, visit:
94 
-    		 http://docs.docker.com/userguide/
90 
+        latest: Pulling from library/hello-world
91 
+        c04b14da8d14: Pull complete
92 
+        Digest: sha256:0256e8a36e2070f7bf2d0b0763dbabdd67798512411de4cdcf9431a1feb60fd9
93 
+        Status: Downloaded newer image for hello-world:latest
95 94
96 
-### Install with the script
95 
+        Hello from Docker!
96 
+        This message shows that your installation appears to be working correctly.
97 
+
98 
+        To generate this message, Docker took the following steps:
99 
+         1. The Docker client contacted the Docker daemon.
100 
+         2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
101 
+         3. The Docker daemon created a new container from that image which runs the
102 
+            executable that produces the output you are currently reading.
103 
+         4. The Docker daemon streamed that output to the Docker client, which sent it
104 
+            to your terminal.
105 
+
106 
+        To try something more ambitious, you can run an Ubuntu container with:
107 
+         $ docker run -it ubuntu bash
97 108
98 
-You use the same installation procedure for all versions of CentOS.
109 
+        Share images, automate workflows, and more with a free Docker Hub account:
110 
+         https://hub.docker.com
111 
+
112 
+        For more examples and ideas, visit:
113 
+         https://docs.docker.com/engine/userguide/
114 
+
115 
+If you need to add an HTTP Proxy, set a different directory or partition for the
116 
+Docker runtime files, or make other customizations, read our Systemd article to
117 
+learn how to [customize your Systemd Docker daemon options](../../admin/systemd.md).
118 
+
119 
+### Install with the script
99 120
100 121 
 1. Log into your machine as a user with `sudo` or `root` privileges.
101 122
102 
-2. Make sure your existing yum packages are up-to-date.
123 
+2. Make sure your existing packages are up-to-date.
103 124
104 
-		$ sudo yum update
125 
+    ```bash
126 
+    $ sudo yum update
127 
+    ```
105 128
106 129 
 3. Run the Docker installation script.
107 130
108 
-		$ curl -fsSL https://get.docker.com/ | sh
131 
+    ```bash
132 
+    $ curl -fsSL https://get.docker.com/ | sh
133 
+    ```
109 134
110 
-4. Start the Docker daemon.
135 
+    This script adds the `docker.repo` repository and installs Docker.
111 136
112 
-		$ sudo service docker start
137 
+4. Enable the service.
113 138
114 
-5. Verify `docker` is installed correctly by running a test image in a container.
139 
+    ```bash
140 
+    $ sudo systemctl enable docker.service
141 
+    ```
115 142
116 
-		$ sudo docker run hello-world
143 
+5. Start the Docker daemon.
144 
+
145 
+    ```bash
146 
+    $ sudo systemctl start docker
147 
+    ```
148 
+
149 
+6. Verify `docker` is installed correctly by running a test image in a container.
117 150
118 
-## Create a docker group
151 
+    ```bash
152 
+    $ sudo docker run hello-world
153 
+    ```
154 
+
155 
+If you need to add an HTTP Proxy, set a different directory or partition for the
156 
+Docker runtime files, or make other customizations, read our Systemd article to
157 
+learn how to [customize your Systemd Docker daemon options](../../admin/systemd.md).
158 
+
159 
+## Create a docker group
119 160
120 161 
 The `docker` daemon binds to a Unix socket instead of a TCP port. By default
121 162 
 that Unix socket is owned by the user `root` and other users can access it with
... ... 
@@ -135,50 +176,59 @@ To create the `docker` group and add your user:
135 135
136 136 
 2. Create the `docker` group.
137 137
138 
-    `sudo groupadd docker`
138 
+    ```bash
139 
+    $ sudo groupadd docker
140 
+    ```
139 141
140 142 
 3. Add your user to `docker` group.
141 143
142 
-    `sudo usermod -aG docker your_username`
144 
+    ```bash
145 
+    $ sudo usermod -aG docker your_username`
146 
+    ```
143 147
144 148 
 4. Log out and log back in.
145 149
146 150 
     This ensures your user is running with the correct permissions.
147 151
148 
-5. Verify your work by running `docker` without `sudo`.
152 
+5. Verify that your user is in the docker group by running `docker` without `sudo`.
149 153
150 
-			$ docker run hello-world
154 
+    ```bash
155 
+    $ docker run hello-world
156 
+    ```
151 157
152 158 
 ## Start the docker daemon at boot
153 159
154 
-To ensure Docker starts when you boot your system, do the following:
155 
-
156 
-    $ sudo chkconfig docker on
157 
-
158 
-If you need to add an HTTP Proxy, set a different directory or partition for the
159 
-Docker runtime files, or make other customizations, read our Systemd article to
160 
-learn how to [customize your Systemd Docker daemon options](../../admin/systemd.md).
160 
+Configure the Docker daemon to start automatically when the host starts:
161 161
162 
+```bash
163 
+$ sudo systemctl enable docker
164 
+```
162 165
163 166 
 ## Uninstall
164 167
165 
-You can uninstall the Docker software with `yum`.
168 
+You can uninstall the Docker software with `yum`.
169 
+
170 
+1. List the installed Docker packages.
166 171
167 
-1. List the package you have installed.
172 
+    ```bash
173 
+    $ yum list installed | grep docker
168 174
169 
-		$ yum list installed | grep docker
170 
-		yum list installed | grep docker
171 
-		docker-engine.x86_64                1.7.1-0.1.el7@/docker-engine-1.7.1-0.1.el7.x86_64
175 
+    docker-engine.x86_64     1.7.1-0.1.el7@/docker-engine-1.7.1-0.1.el7.x86_64
176 
+    ```
172 177
173 178 
 2. Remove the package.
174 179
175 
-		$ sudo yum -y remove docker-engine.x86_64
180 
+    ```bash
181 
+    $ sudo yum -y remove docker-engine.x86_64
182 
+    ```
176 183
177 
-	This command does not remove images, containers, volumes, or user created
184 
+	This command does not remove images, containers, volumes, or user-created
178 185 
 	configuration files on your host.
179 186
180 
-3. To delete all images, containers, and volumes run the following command:
187 
+3. To delete all images, containers, and volumes, run the following command:
181 188
182 
-		$ rm -rf /var/lib/docker
189 
+    ```bash
190 
+    $ rm -rf /var/lib/docker
191 
+    ```
183 192
184 193 
 4. Locate and delete any user-created configuration files.