Create a base Docker image using debootstrap utility.
Install debootstrap package to create a minimal Debian base system.
$ sudo apt-get install debootstrap
Reading package lists... Done Building dependency tree Reading state information... Done The following NEW packages will be installed: debootstrap 0 upgraded, 1 newly installed, 0 to remove and 1 not upgraded. Need to get 66.5 kB of archives. After this operation, 264 kB of additional disk space will be used. Get:1 http://ftp.task.gda.pl/debian stretch/main amd64 debootstrap all 1.0.89 [66.5 kB] Fetched 66.5 kB in 0s (216 kB/s) Selecting previously unselected package debootstrap. (Reading database ... 47906 files and directories currently installed.) Preparing to unpack .../debootstrap_1.0.89_all.deb ... Unpacking debootstrap (1.0.89) ... Processing triggers for man-db (2.7.6.1-2) ... Setting up debootstrap (1.0.89) ...
Install dirmngr to enable network operations for managing and downloading certificates.
$ sudo apt-get install dirmngr
Reading package lists... Done Building dependency tree Reading state information... Done Suggested packages: dbus-user-session pinentry-gnome3 tor The following NEW packages will be installed: dirmngr 0 upgraded, 1 newly installed, 0 to remove and 1 not upgraded. Need to get 595 kB of archives. After this operation, 1,110 kB of additional disk space will be used. Get:1 http://ftp.task.gda.pl/debian stretch/main amd64 dirmngr amd64 2.1.18-8~deb9u1 [595 kB] Fetched 595 kB in 0s (1,599 kB/s) Selecting previously unselected package dirmngr. (Reading database ... 47969 files and directories currently installed.) Preparing to unpack .../dirmngr_2.1.18-8~deb9u1_amd64.deb ... Unpacking dirmngr (2.1.18-8~deb9u1) ... Processing triggers for man-db (2.7.6.1-2) ... Setting up dirmngr (2.1.18-8~deb9u1) ...
Download and store Debian signing key in case you use different Debian-based Linux distribution.
$ sudo apt-key --keyring /etc/apt/trusted.gpg.d/debian-archive-stretch-stable.gpg adv --keyserver pgpkeys.mit.edu --recv-keys EF0F382A1A7B6500
Executing: /tmp/apt-key-gpghome.8RuwguajVm/gpg.1.sh --keyserver pgpkeys.mit.edu --recv-keys EF0F382A1A7B6500 gpg: key EF0F382A1A7B6500: public key "Debian Stable Release Key (9/stretch) <debian-release@lists.debian.org>" imported gpg: Total number processed: 1 gpg: imported: 1
Create a base Debian system with enabled main, contrib, and non-free components. Install dirmngr and apt-transport-https packages during this process.
$ sudo debootstrap --keyring /etc/apt/trusted.gpg.d/debian-archive-stretch-stable.gpg --force-check-gpg --variant=minbase --components=main,contrib,non-free --include=dirmngr,apt-transport-https --arch=amd64 stretch debian-stretch http://deb.debian.org/debian/
I: Retrieving InRelease I: Retrieving Release I: Retrieving Release.gpg I: Checking Release signature I: Valid Release signature (key id 067E3C456BAE240ACEE88F6FEF0F382A1A7B6500) I: Retrieving Packages I: Validating Packages I: Retrieving Packages I: Validating Packages I: Retrieving Packages I: Validating Packages I: Resolving dependencies of required packages... I: Resolving dependencies of base packages... I: Found additional required dependencies: libaudit-common libaudit1 libbz2-1.0 libcap-ng0 libdb5.3 libdebconfclient0 libgcrypt20 libgpg-error0 liblz4-1 libncursesw5 libsemanage-common libsemanage1 libsystemd0 libudev1 libustr-1.0-1 I: Found additional base dependencies: adduser debian-archive-keyring gpgv libapt-pkg5.0 libassuan0 libcurl3-gnutls libffi6 libgmp10 libgnutls30 libgssapi-krb5-2 libhogweed4 libidn11 libidn2-0 libk5crypto3 libkeyutils1 libkrb5-3 libkrb5support0 libksba8 libldap-2.4-2 libldap-common libnettle6 libnghttp2-14 libnpth0 libp11-kit0 libpsl5 librtmp1 libsasl2-2 libsasl2-modules-db libssh2-1 libstdc++6 libtasn1-6 libunistring0 I: Checking component main on http://deb.debian.org/debian... I: Retrieving libacl1 2.2.52-3+b1 I: Validating libacl1 2.2.52-3+b1 I: Retrieving adduser 3.115 I: Validating adduser 3.115 I: Retrieving apt 1.4.8 I: Validating apt 1.4.8 I: Retrieving apt-transport-https 1.4.8 I: Validating apt-transport-https 1.4.8 [...] I: Chosen extractor for .deb packages: dpkg-deb I: Extracting libacl1... I: Extracting libattr1... I: Extracting libaudit-common... I: Extracting libaudit1... [...] I: Installing core packages... I: Unpacking required packages... I: Unpacking libacl1:amd64... I: Unpacking libattr1:amd64... I: Unpacking libaudit-common... I: Unpacking libaudit1:amd64... [...] I: Configuring required packages... I: Configuring gcc-6-base:amd64... I: Configuring lsb-base... I: Configuring sensible-utils... I: Configuring ncurses-base... [...] I: Unpacking the base system... I: Unpacking adduser... I: Unpacking apt... I: Unpacking apt-transport-https... I: Unpacking libapt-pkg5.0:amd64... [...] I: Configuring the base system... I: Configuring libnpth0:amd64... I: Configuring libnettle6:amd64... I: Configuring libnghttp2-14:amd64... I: Configuring libldap-common... [...] I: Base system installed successfully.
Initial base system size.
$ sudo du --human-readable --summarize debian-stretch
189M debian-stretch
Mount udev, devpts, proc, and sysfs filesystems inside the created base system. You can skip this step for basic operations like these performed here.
$ sudo mount --bind /dev debian-stretch/dev $ sudo mount --bind /dev/pts debian-stretch/dev/pts $ sudo mount --bind /proc debian-stretch/proc $ sudo mount --bind /sys debian-stretch/sys
Change root directory.
$ sudo chroot debian-stretch
Assume yes answer for apt operations.
root@debian:/# echo "APT::Get::Assume-Yes \"true\";" | tee /etc/apt/apt.conf.d/10-assume_yes
APT::Get::Assume-Yes "true";
Install git utility inside the base system.
root@debian:/# apt-get install --no-install-recommends git
Remove non-essential packages from the created base system.
root@debian:/# apt-get remove --allow-remove-essential e2fsprogs e2fslibs nano pinentry-curses whiptail kmod iptables iproute2 dmidecode
Remove downloaded packages from the local repository.
root@debian:/# apt-get clean
Remove downloaded package lists.
root@debian:/# find /var/lib/apt/lists/ -maxdepth 2 -type f -delete
Exit chroot environment.
root@debian:/# exit
Detach filesystems mounted earlier inside the created base system.
$ sudo umount debian-stretch/dev/pts $ sudo umount debian-stretch/dev $ sudo umount debian-stretch/proc $ sudo umount debian-stretch/sys
Base system size after performed operations.
$ sudo du --human-readable --summarize debian-stretch
188M debian-stretch
Create an archive with the Debian base system.
$ sudo tar --verbose --create --file debian-stretch.tar --directory debian-stretch .
Inspect archive size.
$ sudo du --human-readable debian-stretch.tar
173M debian-stretch.tar
Use docker to import the image.
$ cat debian-stretch.tar | docker import - debian-stretch
Create the simplest possible dockerfile using Nginx to test the created base image.
$ mkdir nginx
$ cat << EOF | tee nginx/Dockerfile FROM "debian-stretch" RUN \\ apt-get update && \\ apt-get install nginx WORKDIR /etc/nginx CMD ["nginx", "-g", "daemon off;"] EXPOSE 80 EOF
FROM "debian-stretch" RUN \ apt-get update && \ apt-get install nginx WORKDIR /etc/nginx CMD ["nginx", "-g", "daemon off;"] EXPOSE 80
Build an image.
$ docker build -t nginx-test nginx
Sending build context to Docker daemon 2.048kB Step 1/5 : FROM "debian-stretch" ---> aa30c1dd3f7b Step 2/5 : RUN apt-get update && apt-get install nginx ---> Running in 6633f8d4b8ad Ign:1 http://cdn-fastly.deb.debian.org/debian stretch InRelease Get:2 http://cdn-fastly.deb.debian.org/debian stretch Release [118 kB] Get:3 http://cdn-fastly.deb.debian.org/debian stretch Release.gpg [2434 B] Get:4 http://cdn-fastly.deb.debian.org/debian stretch/main amd64 Packages [7123 kB] Get:5 http://cdn-fastly.deb.debian.org/debian stretch/main Translation-en [5393 kB] Get:6 http://cdn-fastly.deb.debian.org/debian stretch/contrib amd64 Packages [50.9 kB] Get:7 http://cdn-fastly.deb.debian.org/debian stretch/contrib Translation-en [45.9 kB] Get:8 http://cdn-fastly.deb.debian.org/debian stretch/non-free amd64 Packages [78.0 kB] Get:9 http://cdn-fastly.deb.debian.org/debian stretch/non-free Translation-en [79.2 kB] Fetched 12.9 MB in 4s (2767 kB/s) Reading package lists... Reading package lists... Building dependency tree... Reading state information... The following additional packages will be installed: fontconfig-config fonts-dejavu-core geoip-database libbsd0 libfontconfig1 libfreetype6 libgd3 libgeoip1 libicu57 libjbig0 libjpeg62-turbo libnginx-mod-http-auth-pam libnginx-mod-http-dav-ext libnginx-mod-http-echo libnginx-mod-http-geoip libnginx-mod-http-image-filter libnginx-mod-http-subs-filter libnginx-mod-http-upstream-fair libnginx-mod-http-xslt-filter libnginx-mod-mail libnginx-mod-stream libpng16-16 libssl1.1 libtiff5 libwebp6 libx11-6 libx11-data libxau6 libxcb1 libxdmcp6 libxml2 libxpm4 libxslt1.1 nginx-common nginx-full sgml-base ucf xml-core Suggested packages: libgd-tools geoip-bin fcgiwrap nginx-doc ssl-cert sgml-base-doc debhelper The following NEW packages will be installed: fontconfig-config fonts-dejavu-core geoip-database libbsd0 libfontconfig1 libfreetype6 libgd3 libgeoip1 libicu57 libjbig0 libjpeg62-turbo libnginx-mod-http-auth-pam libnginx-mod-http-dav-ext libnginx-mod-http-echo libnginx-mod-http-geoip libnginx-mod-http-image-filter libnginx-mod-http-subs-filter libnginx-mod-http-upstream-fair libnginx-mod-http-xslt-filter libnginx-mod-mail libnginx-mod-stream libpng16-16 libssl1.1 libtiff5 libwebp6 libx11-6 libx11-data libxau6 libxcb1 libxdmcp6 libxml2 libxpm4 libxslt1.1 nginx nginx-common nginx-full sgml-base ucf xml-core 0 upgraded, 39 newly installed, 0 to remove and 0 not upgraded. Need to get 18.6 MB of archives. After this operation, 58.9 MB of additional disk space will be used. Get:1 http://cdn-fastly.deb.debian.org/debian stretch/main amd64 libxau6 amd64 1:1.0.8-1 [20.7 kB] Get:2 http://cdn-fastly.deb.debian.org/debian stretch/main amd64 sgml-base all 1.29 [14.8 kB] Get:3 http://cdn-fastly.deb.debian.org/debian stretch/main amd64 libssl1.1 amd64 1.1.0f-3+deb9u1 [1342 kB] [...] Fetched 18.6 MB in 4s (3877 kB/s) Selecting previously unselected package libxau6:amd64. (Reading database ... 9191 files and directories currently installed.) Preparing to unpack .../00-libxau6_1%3a1.0.8-1_amd64.deb ... Unpacking libxau6:amd64 (1:1.0.8-1) ... Selecting previously unselected package sgml-base. Preparing to unpack .../01-sgml-base_1.29_all.deb ... Unpacking sgml-base (1.29) ... Selecting previously unselected package libssl1.1:amd64. Preparing to unpack .../02-libssl1.1_1.1.0f-3+deb9u1_amd64.deb ... [...] Removing intermediate container 6633f8d4b8ad ---> 70f98486d676 Step 3/5 : WORKDIR /etc/nginx Removing intermediate container a6a39756a14f ---> be74e0f6e790 Step 4/5 : CMD ["nginx", "-g", "daemon off;"] ---> Running in 6cd6d572d594 Removing intermediate container 6cd6d572d594 ---> 6d4869b43380 Step 5/5 : EXPOSE 80 ---> Running in a60697b44e55 Removing intermediate container a60697b44e55 ---> f565d7bbf5ba Successfully built f565d7bbf5ba Successfully tagged nginx-test:latest
Run Nginx process inside the container (in foreground) using port 8080.
$ docker run -p 8080:80 --name nginx-test nginx-test
Request and display the initial welcome web-page to test it.
$ wget --quiet --output-document - http://$(hostname):8080
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>
<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>
<p><em>Thank you for using nginx.</em></p>
</body>
</html>
You can use a different terminal to verify the redirected port.
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 84f17e2b8467 nginx-test "nginx -g 'daemon of…" About a minute ago Up About a minute 0.0.0.0:8080->80/tcp nginx-test
Now you can improve it further for your own needs.