no se ha encontrado el comando docker aunque esté instalado con apt-get

IMPORTANTE-en el paquete de ubuntu docker es algo completamente diferente (evitarlo):

Problema siguiente para ver qué pasa si algún paquete tiene que mencionar docker

dpkg -l|grep docker

Si solo coincide está siguiendo entonces usted no tiene docker instalado a continuación es un paquete no relacionado

Docker-Bandeja del sistema para aplicaciones docklet KDE3 / GNOME2

Si ves algo similar a lo siguiente, entonces tienes docker instalado

ii docker-ce 18.06.1~ce~2.1.rc1-0~ubuntu  amd64  Docker: the open-source application container engine

NOTA-ubuntu el paquete docker.io no está recibiendo actualizaciones (obsoleto NO usar )

En su lugar hacer esto : instale la última versión de docker en Linux ejecutando lo siguiente:

  sudo curl -sSL https://get.docker.com/ | sh
# sudo curl -sSL https://test.docker.com | sh  # get dev pipeline version

Aquí hay una salida típica (ubuntu 16.04 )

apparmor is enabled in the kernel and apparmor utils were already installed
+ sudo -E sh -c apt-key adv --keyserver hkp://ha.pool.sks-keyservers.net:80 --recv-keys 58118E89F3A912897C070ADBF76221572C52609D
Executing: /tmp/tmp.rAAGu0P85R/gpg.1.sh --keyserver
hkp://ha.pool.sks-keyservers.net:80
--recv-keys
58118E89F3A912897C070ADBF76221572C52609D
gpg: requesting key 2C52609D from hkp server ha.pool.sks-keyservers.net
gpg: key 2C52609D: "Docker Release Tool (releasedocker) <[email protected]>" 1 new signature
gpg: Total number processed: 1
gpg:         new signatures: 1
+ break
+ sudo -E sh -c apt-key adv -k 58118E89F3A912897C070ADBF76221572C52609D >/dev/null
+ sudo -E sh -c mkdir -p /etc/apt/sources.list.d
+ dpkg --print-architecture
+ sudo -E sh -c echo deb [arch=amd64] https://apt.dockerproject.org/repo ubuntu-xenial main > /etc/apt/sources.list.d/docker.list
+ sudo -E sh -c sleep 3; apt-get update; apt-get install -y -q docker-engine
Hit:1 http://repo.steampowered.com/steam precise InRelease
Hit:2 http://download.virtualbox.org/virtualbox/debian xenial InRelease                                                           
Ign:3 http://dl.google.com/linux/chrome/deb stable InRelease                                                                      
Hit:4 http://dl.google.com/linux/chrome/deb stable Release                                                                        
Hit:5 http://archive.canonical.com/ubuntu xenial InRelease                                                                        
Hit:6 http://mirror.cc.columbia.edu/pub/linux/ubuntu/archive xenial InRelease                                                     
Hit:7 http://mirror.cc.columbia.edu/pub/linux/ubuntu/archive xenial-updates InRelease                                             
Hit:8 http://ppa.launchpad.net/me-davidsansome/clementine/ubuntu xenial InRelease                                                 
Ign:9 http://repo.mongodb.org/apt/debian wheezy/mongodb-org/3.2 InRelease                                                         
Hit:10 http://mirror.cc.columbia.edu/pub/linux/ubuntu/archive xenial-backports InRelease                                          
Hit:11 http://repo.mongodb.org/apt/debian wheezy/mongodb-org/3.2 Release                                                          
Hit:12 http://mirror.cc.columbia.edu/pub/linux/ubuntu/archive xenial-security InRelease                                           
Hit:14 http://ppa.launchpad.net/numix/ppa/ubuntu xenial InRelease                                                                 
Ign:15 http://linux.dropbox.com/ubuntu wily InRelease                                                                             
Ign:16 http://repo.vivaldi.com/stable/deb stable InRelease                                                                        
Hit:17 http://repo.vivaldi.com/stable/deb stable Release                                                                          
Get:18 http://linux.dropbox.com/ubuntu wily Release [6,596 B]            
Get:19 https://apt.dockerproject.org/repo ubuntu-xenial InRelease [20.6 kB]    
Ign:20 http://packages.amplify.nginx.com/ubuntu xenial InRelease                      
Hit:22 http://packages.amplify.nginx.com/ubuntu xenial Release
Hit:23 https://deb.opera.com/opera-beta stable InRelease
Hit:26 https://deb.opera.com/opera-developer stable InRelease
Get:28 https://apt.dockerproject.org/repo ubuntu-xenial/main amd64 Packages [1,719 B]
Hit:29 https://packagecloud.io/slacktechnologies/slack/debian jessie InRelease
Fetched 28.9 kB in 1s (17.2 kB/s)
Reading package lists... Done
W: http://repo.mongodb.org/apt/debian/dists/wheezy/mongodb-org/3.2/Release.gpg: Signature by key 42F3E95A2C4F08279C4960ADD68FA50FEA312927 uses weak digest algorithm (SHA1)
Reading package lists...
Building dependency tree...
Reading state information...
The following additional packages will be installed:
  aufs-tools cgroupfs-mount
The following NEW packages will be installed:
  aufs-tools cgroupfs-mount docker-engine
0 upgraded, 3 newly installed, 0 to remove and 17 not upgraded.
Need to get 14.6 MB of archives.
After this operation, 73.7 MB of additional disk space will be used.
Get:1 http://mirror.cc.columbia.edu/pub/linux/ubuntu/archive xenial/universe amd64 aufs-tools amd64 1:3.2+20130722-1.1ubuntu1 [92.9 kB]
Get:2 http://mirror.cc.columbia.edu/pub/linux/ubuntu/archive xenial/universe amd64 cgroupfs-mount all 1.2 [4,970 B]
Get:3 https://apt.dockerproject.org/repo ubuntu-xenial/main amd64 docker-engine amd64 1.11.2-0~xenial [14.5 MB]
Fetched 14.6 MB in 7s (2,047 kB/s)
Selecting previously unselected package aufs-tools.
(Reading database ... 427978 files and directories currently installed.)
Preparing to unpack .../aufs-tools_1%3a3.2+20130722-1.1ubuntu1_amd64.deb ...
Unpacking aufs-tools (1:3.2+20130722-1.1ubuntu1) ...
Selecting previously unselected package cgroupfs-mount.
Preparing to unpack .../cgroupfs-mount_1.2_all.deb ...
Unpacking cgroupfs-mount (1.2) ...
Selecting previously unselected package docker-engine.
Preparing to unpack .../docker-engine_1.11.2-0~xenial_amd64.deb ...
Unpacking docker-engine (1.11.2-0~xenial) ...
Processing triggers for libc-bin (2.23-0ubuntu3) ...
Processing triggers for man-db (2.7.5-1) ...
Processing triggers for ureadahead (0.100.0-19) ...
Processing triggers for systemd (229-4ubuntu6) ...
Setting up aufs-tools (1:3.2+20130722-1.1ubuntu1) ...
Setting up cgroupfs-mount (1.2) ...
Setting up docker-engine (1.11.2-0~xenial) ...
Processing triggers for libc-bin (2.23-0ubuntu3) ...
Processing triggers for systemd (229-4ubuntu6) ...
Processing triggers for ureadahead (0.100.0-19) ...
+ sudo -E sh -c docker version
Client:
 Version:      1.11.2
 API version:  1.23
 Go version:   go1.5.4
 Git commit:   b9f10c9
 Built:        Wed Jun  1 22:00:43 2016
 OS/Arch:      linux/amd64

Server:
 Version:      1.11.2
 API version:  1.23
 Go version:   go1.5.4
 Git commit:   b9f10c9
 Built:        Wed Jun  1 22:00:43 2016
 OS/Arch:      linux/amd64

If you would like to use Docker as a non-root user, you should now consider
adding your user to the "docker" group with something like:

  sudo usermod -aG docker stens

Remember that you will have to log out and back in for this to take effect!

Aquí están las instrucciones de instalación detalladas subyacentes que, como puede ver, vienen incluidas en la técnica anterior ... Por encima de un trazador de líneas le da lo mismo que :

Https://docs.docker.com/engine/installation/linux/ubuntulinux /

Una vez instalado, puede ver qué paquetes de docker se instalaron emitiendo

dpkg -l|grep docker

ii  docker-engine                               1.11.2-0~xenial                                     amd64        Docker: the open-source application container engine

Ahora las actualizaciones de Docker se instalarán en el futuro cuando emita

sudo apt-get update
sudo apt-get upgrade

Echa un vistazo a

 ls -latr /etc/apt/sources.list.d/*docker*
-rw-r--r-- 1 root root 202 Jun 23 10:01 /etc/apt/sources.list.d/docker.list.save
-rw-r--r-- 1 root root  71 Jul  4 11:32 /etc/apt/sources.list.d/docker.list


cat /etc/apt/sources.list.d/docker.list

deb [arch=amd64] https://apt.dockerproject.org/repo ubuntu-xenial main

sudo apt-get install docker 

Es una biblioteca diferente en ubuntu.

Use sudo apt-get install docker.io para instalar la docker correcta.

CONFIGURAR EL REPOSITORIO

Para Ubuntu 14.04/16.04/16.10/17.04:

sudo add-apt-repository "deb [arch=amd64] \
     https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"

Para Ubuntu 17.10:

sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu zesty stable"

Añadir la clave GPG oficial de Docker:

$ curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -

Luego instale

$ sudo apt-get update && sudo apt-get -y install docker-ce

Ejecute el comando Docker con sudo:

sudo docker <your command>

Como dice la documentación :

El demonio docker se enlaza a un socket Unix en lugar de a un puerto TCP. Por defecto, el socket Unix es propiedad del usuario root y otros usuarios solo pueden acceder a él usando sudo. El demonio docker siempre se ejecuta como usuario root.

Si no desea utilizar sudo cuando utilice el comando docker, cree un grupo Unix llamado docker y añadir usuarios a él. Cuando el demonio docker empezar, hace que la propiedad del socket Unix sea leída/escrita por el grupo docker.