If you only have a single docker machine, you simply do:

    $ docker-machine ssh

If you have multiple machines, you need to find your &quot;machine name&quot; first:

    $ docker-machine ls
    NAME      ACTIVE   DRIVER       STATE     URL                         SWARM   DOCKER    ERRORS
    default   *        virtualbox   Running   tcp://192.168.99.101:2376           v1.10.2 

From the above, you can see that **default** is the name of your machine and you can ssh as follows:

    $ docker-machine ssh default

When you&#39;re in, it&#39;s a simple case of sudo-ing to root

    docker@default:~$ sudo -i
    Boot2Docker version 1.10.2, build master : 611be10 - Mon Feb 22 22:47:06 UTC 2016
    Docker version 1.10.2, build c3959b1
    root@default:~# 

Edited: Also, as @MediaVince mentioned you can use the following credentials:

user: **docker**

pwd: **tcuser**

just type

    $ docker-machine ssh your_environment

and then to be root

    $ sudo -i

hope it helps

Login via ssh as `docker` user: 

    $ ssh docker@&lt;docker-machine-ip&gt;

&gt; Password: tcuser

Then you can change on `root` user, just run `sudo su root`

Ok the key was not to do &quot;su root&quot; but rather &quot;su sudo&quot;. It then doesn&#39;t ask for root password.

Say I have two networkx graphs, `G` and `H`:

    G=nx.Graph()
    fromnodes=[0,1,1,1,1,1,2]
    tonodes=[1,2,3,4,5,6,7]
    for x,y in zip(fromnodes,tonodes):
        G.add_edge(x,y)

    H=nx.Graph()
    fromnodes=range(2,8)
    tonodes=range(8,14)
    for x,y in zip(fromnodes,tonodes):
        H.add_edge(x,y)

**What is the best way to join the two networkx graphs?**  

I&#39;d like to preserve the node names (note the common nodes, 2 to 7). When I used `nx.disjoint_union(G,H)`, this did not happen:

    &gt;&gt;&gt; G.nodes()
    [0, 1, 2, 3, 4, 5, 6, 7]
    &gt;&gt;&gt; H.nodes()
    [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13]
    &gt;&gt;&gt; Un= nx.disjoint_union(G,H)
    &gt;&gt;&gt; Un.nodes()
    [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19]
    # 
The `H` node labels were changed (not what I want). I want to join the graphs at the nodes with the same number.

*Note. This is not a duplicate of https://stackoverflow.com/questions/21806751/combine-two-weighted-graphs-in-networkx.* 

Combine (join) networkx Graphs

I am trying to filter all the elements in an array which are bigger than 10 to a new array. I am intentionally not using `Array.prototype.filter()` since I want to learn the `reduce()` method. Here is the code I was playing with

&lt;!-- begin snippet: js hide: false --&gt;

&lt;!-- language: lang-js --&gt;

    var collection = [3, 5, 11, 23, 1];

    // fileter all the elements bigger than 10 to a new array

    var output = collection.reduce(function(filteredArr, collectionElemet) {
      if (collectionElemet &gt; 10) {
        return filteredArr.push(collectionElemet);
      }
    }, []);

&lt;!-- end snippet --&gt;

I was expecting that `filteredArr` would be initialized with an empty array at the time of first callback execution as it happens with many examples provided [here][1]. But when I run this code, I get the error
`Cannot read property &#39;push&#39; of undefined`, where am I messing it up? Thank you!


  [1]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/Reduce

Why Array.prototype.reduce() is not taking an empty array as accumulator?

Haven&#39;t found an answer anywhere... I created a VM (boot2docker) using docker-machine. I need to edit some files using root.

What is the root password in boot2docker?

docker-machine boot2docker root password

<p>Haven't found an answer anywhere... I created a VM (boot2docker) using docker-machine. I need to edit some files using root.</p>
<p>What is the root password in boot2docker?</p>


I run `docker images` and get something like this:

    REPOSITORY                       TAG                 IMAGE ID            CREATED             VIRTUAL SIZE
    docker.io/postgres               latest              a7d662bede59        2 weeks ago         265.3 MB
    docker.io/ubuntu                 latest              91e54dfb1179        2 weeks ago         188.3 MB

Look at **CREATED** column. I want to know what image created earlier with hours, minutes, seconds. Similar with containers, for command `docker ps -a`. How to view exact dates?

How to get exact date for docker images?

I&#39;m building a new Docker image based on the standard Ubuntu 14.04 image. 

Here&#39;s my *Dockerfile*:

    FROM ubuntu:14.04
    RUN apt-get update -y
    RUN apt-get install -y nginx git python-setuptools python-dev
    RUN easy_install pip
    ADD . /code
    WORKDIR /code
    RUN pip install -r requirements.txt # only &#39;django&#39; for now
    ENV projectname myproject
    EXPOSE 80 8000
    WORKDIR ${projectname}
    CMD [&#39;python&#39;, &#39;manage.py&#39;, &#39;runserver&#39;, &#39;0.0.0.0:80&#39;]

When I try to run this image, I get this error...

 

&gt;    /bin/sh: 1: [python,: not found

But if I open a shell when running the image, running `python` opens the interactive prompt as expected. 

Why can&#39;t I invoke `python` through `CMD` in the Dockerfile?

Docker image error: &quot;/bin/sh: 1: [python,: not found&quot;

When running Docker for a long time, there are a lot of images in system. How can I remove all unused Docker images at once safety to free up the storage?

In addition, I also want to remove images pulled months ago, which have the correct `TAG`.

So, I&#39;m not asking for removing untagged images only. I&#39;m searching for a way to remove general unused images, which includes both untagged and other images such as pulled months ago with correct `TAG`.



How to remove old and unused Docker images

I am new to the docker world. I have to invoke a shell script that takes command line arguments through a docker container.
Ex: My shell script looks like:

    #!bin/bash
    echo $1

Dockerfile looks like this:

    FROM ubuntu:14.04
    COPY ./file.sh /
    CMD /bin/bash file.sh

I am not sure how to pass the arguments while running the container

How to pass arguments to Shell Script through docker run

I am trying to automate setting up a developer environment on Mac. Part of that setup is installing the [Docker Toolbox](https://www.docker.com/toolbox). I cannot find any documentation on how do to this via command line. How can I automate this installation (must be triggered via command line)?  

---
**Update:** As pointed out in a commend by [Dennis](https://stackoverflow.com/questions/32744780/install-docker-toolbox-on-a-mac-via-command-line?noredirect=1#comment71074157_32744780) 
&gt; [Docker for Mac](https://docs.docker.com/docker-for-mac/) now exists, which is an alternative to Docker Toolbox. You can get it via the homebrew cask: `brew cask install docker; open /Applications/Docker.app`

Install Docker Toolbox on a Mac via command line

How does one get the size of a Docker image **before** they pull it to their machine?

Get the size of a Docker image before a pull?

I want to spawn 3 services in the &quot;host&quot; net using docker-compose. Here is my docker-compose.yml file:

    version: &#39;2&#39;
    services:
      mysql:
        image: mysql
        net: &quot;host&quot;
      nginx:
        image: nginx
        net: &quot;host&quot;
      app:
        image: tomcat
        net: &quot;host&quot;

I got the following error:

    $ docker-compose up
    [31mERROR[0m: Validation failed in file &#39;.\docker-compose.yml&#39;, reason(s):
    Unsupported config option for services.app: &#39;net&#39;
    Unsupported config option for services.mysql: &#39;net&#39;
    Unsupported config option for services.nginx: &#39;net&#39;

I&#39;m using boot2docker on windows.

Docker, and Docker-compose version:

    $ docker -v
    Docker version 1.10.2, build c3959b1
    $ docker-compose -version
    docker-compose version 1.6.0, build cdb920a

If I run all services manually by using `docker run --net = &quot;host&quot;` everything is working fine.

In the documentation I read that **net** command is **supported in docker-compose**:

&gt; **net**
&gt;
&gt; Networking mode. Use the same values as the docker client --net parameter.
&gt; 
&gt; net: &quot;bridge&quot;
&gt; 
&gt; net: &quot;none&quot;
&gt; 
&gt; net: &quot;container:[name or id]&quot;
&gt; 
&gt; net: &quot;host&quot;

https://docs.docker.com/v1.6/compose/yml/#net

What am I doing wrong?


Docker compose, running containers in net:host

I downloaded and installed Docker for Windows 1.12.1 which in turn installed the docker-machine and docker-compose. I did not install &quot;Docker Toolbox&quot; since its a duplicate of what was installed and my system meets the [requirements][1].

Everything seems to work fine except for docker-machine, I&#39;m running through a tutorial and when I run various docker-machine commands like &quot;ip&quot; or &quot;env&quot; I get the following message.

    Error: No machine name(s) specified and no &quot;default&quot; machine exists.
So when I do a &quot;docker-machine ls&quot; there is nothing in the list even though I do have a Hyper-V docker machine installed and docker commands work fine.

    C:\tmp&gt;docker-machine ls
    NAME   ACTIVE   DRIVER   STATE   URL   SWARM   DOCKER   ERRORS
    C:\tmp&gt;

Am I missing something here? Did I miss something in the documentation? If so can someone please point me in the right direction to fix this?

Thanks for any help,

Jim


  [1]: https://docs.docker.com/docker-for-windows/#/what-to-know-before-you-install

docker-machine: no machine name, no &quot;default&quot; exists

I use `docker logs [container-name]` to see the logs of a specific container.

Is there an elegant way to clear these logs?


Docker: How to clear the logs properly for a Docker container?

I tried this on my Windows 10 machine:

Dockerfile:

&lt;!-- language: lang-none --&gt;

    From microsoft/nanoserver
    CMD [&quot;echo&quot;, &quot;Hello World&quot;]

PS

    C:\FSD\Docker\Trial1&gt; docker build -t lea/leatest .
    Sending build context to Docker daemon  2.048kB
    Step 1/2 : FROM microsoft/nanoserver
    latest: Pulling from microsoft/nanoserver
    bce2fbc256ea: Pulling fs layer
    58f68fa0ceda: Pulling fs layer
    image operating system &quot;windows&quot; cannot be used on this platform



Docker - image operating system &quot;windows&quot; cannot be used on this platform

I am new to Docker, and trying to go through this tutorial setting up MemSQL from a Docker image - http://docs.memsql.com/4.0/setup/docker/ .  I am on a Mac, and the tutorial uses `boot2docker` which seems to have been deprecated.  

The VM needs 4GB memory to run.  The tutorial specifies how to do this with `boot2docker` but I cannot find a way to do this with the docker-machine/docker toolbox. 

Here is the command I am using and the error I am getting just trying to go through the tutorial without altering the boot2docker config.  

    docker run --rm --net=host memsql/quickstart check-system
    Error: MemSQL requires at least 4 GB of memory to run.

How to increase docker-machine memory Mac

I am using docker toolbox on Windows 7 to run docker. (docker version 1.9.1)

As it turns out, the docker machine creates its VM at C:\Users\username\\.docker\machine\machines\default. As I commit the images, the size of VM at this location bloats up. Since it&#39;s Windows, I can&#39;t afford the luxury of space on the C drive. 

Is there any way I can change the location of the default machine?

Change Docker machine location - Windows

EDIT (2/19/21): A lot of time has elapsed since I asked this original question years ago and I&#39;ve seen a flurry of activity since then. I re-selected an answer which I think is consistent with the most localized and safe option for solving this issue (which is typically associated with docker-compose). While docker did introduce the `prune` command, it is generally a dangerous operation and I would be cautious about using it as you may unintentionally impact other applications or setups you have on your machine

--- 

I&#39;ve been having issues with removing Docker volumes with Docker 1.9.1.

I&#39;ve removed all my stopped containers so that `docker ps -a` returns empty.

When I use `docker volume ls`, I&#39;m given a whole host of Docker containers:

    docker volume ls
    DRIVER              VOLUME NAME
    local               a94211ea91d66142886d72ec476ece477bb5d2e7e52a5d73b2f2f98f6efa6e66
    local               4f673316d690ca2d41abbdc9bf980c7a3f8d67242d76562bbd44079f5f438317
    local               eb6ab93effc4b90a2162e6fab6eeeb65bd0e4bd8a9290e1bad503d2a47aa8a78
    local               91acb0f7644aec16d23a70f63f70027899017a884dab1f33ac8c4cf0dabe5f2c
    local               4932e2fbad8f7e6246af96208d45a266eae11329f1adf176955f80ca2e874f69
    local               68fd38fc78a8f02364a94934e9dd3b5d10e51de5b2546e7497eb21d6a1e7b750
    local               7043a9642614dd6e9ca013cdf662451d2b3df6b1dddff97211a65ccf9f4c6d47
    #etc x 50

Since none of these volumes contain anything important, I try to purge all the volumes with `docker volume rm $(docker volume ls -q)`.

In the process, the majority are removed, but I get back:

    Error response from daemon: Conflict: volume is in use
    Error response from daemon: Conflict: volume is in use
    Error response from daemon: Conflict: volume is in use
    Error response from daemon: Conflict: volume is in use
    Error response from daemon: Conflict: volume is in use

For a sizeable portion of them. If I don&#39;t have any containers existing in the first place, how are these volumes being used?



Docker is in volume in use, but there aren&#39;t any Docker containers

I finally figured out how to get docker up and running. 

    docker run --name my-forum-nodebb --link my-forum-redis:redis -p 80:80 -p 443:443 -p 4567:4567 -P -t -i nodebb/docker:ubuntu

I linked it to a redis instance, cool. 

This is from scratch and I assume that when I created the redis instance 

    docker run --name my-forum-redis -d -p 6379:6379 nodebb/docker:ubuntu-redis

it pulls the image from a remote repo?

NodeBB offers a `Dockerfile` https://github.com/NodeBB/NodeBB/blob/master/Dockerfile I am not really quite sure how to use it. I am assuming that I can somehow create a local environment by calling this Dockerfile on my remote.

Is this correct? If so how can I create the local instance pointing to the remote?



How do I run a docker instance from a DockerFile?

How to restart all running docker containers? Mainly looking for a shortcut instead of doing 

&gt; docker restart containerid1 containerid2

Content Type	Original Author	Original Content on Stackoverflow
Question	user1340582	View Question on Stackoverflow
Solution 1 - Docker	Nick De Greek	View Answer on Stackoverflow
Solution 2 - Docker	grimabe	View Answer on Stackoverflow
Solution 3 - Docker	giokoguashvili	View Answer on Stackoverflow
Solution 4 - Docker	user1340582	View Answer on Stackoverflow

docker-machine boot2docker root password

Docker Problem Overview

Docker Solutions

Solution 1 - Docker

Solution 2 - Docker

Solution 3 - Docker

Solution 4 - Docker

Why Array.prototype.reduce() is not taking an empty array as accumulator?

Combine (join) networkx Graphs

Attributions