This is by design. Docker should be running a process in the foreground in your container and it will be spawned as PID 1 within the container&#39;s pid namespace. Docker is designed for process isolation, not for OS virtualization, so there are no other OS processes and daemons running inside the container (like systemd, cron, syslog, etc), only your entrypoint or command you run.

If they included systemd commands, you&#39;d find a lot of things not working since your entrypoint replaces init. Systemd also makes use to cgroups which docker restricts inside of containers since the ability to change cgroups could allow a process to escape the container&#39;s isolation. Without systemd running as init inside your container, there&#39;s no daemon to process your start and stop commands.

I went through [this][1], and as far as the process goes I did that.

[![][2]][2]

But I when I installed the app from play store I am not able to sign in using the `google sign in` button.

I have used Firebase for google sign in. When I am clicking the sign in button the option to choose the account is coming but then it is not signing in or doing anything.

So where possibly am I going wrong?


  [1]: https://developer.android.com/studio/publish/app-signing.html
  [2]: http://i.stack.imgur.com/sA2J1.png

Google sign in not working after publishing in play store

I am currently writing my first Angular 2 Application.
I have an OverviewComponent which has the following simple template:

    &lt;div class=&quot;row&quot;&gt;
      &lt;div class=&quot;col-lg-8&quot;&gt;
        &lt;router-outlet&gt;&lt;/router-outlet&gt;
      &lt;/div&gt;
      &lt;div class=&quot;col-lg-4&quot;&gt;
        &lt;app-list&gt;&lt;/app-list&gt;
      &lt;/div&gt;
    &lt;/div&gt;

when accessing the url `/` my router redirects me to `/overview` which then loads a map within the router-outlet. The `&lt;app-list&gt;` has a list of clickable items which triggers a `&lt;app-detail&gt;` to be displayed instead of the app component. Therefor I pass the id of the referring json file in the url like that: `/details/:id` (in my routes).

All of the above works totally fine. If I now click on one of the list items the details are shown, BUT when I select another list element the view doesn&#39;t change to the new details. The URL does change but the content is not reloaded. How can I achieve a Reinitialization of the DetailComponent?



Angular 2 reload route on param change

**Problem**

It seems `systemd` is not active or available in Ubuntu Docker containers. 

**Setup**

I&#39;m running Docker containers from the `ubuntu:16.04` and `ubuntu:16.10` images.

**Tests**

If I execute:

`systemctl status ssh` in the `16,04` container

the result is the error `Failed to connect to bus: No such file or directory`

In the `16.10` container the error is: `bash: systemctl: command not found`.

If I do `which systemctl` systemctl is found in the `16.04` container but not in the `16.10` container.

I have spotted that `/lib/systemd` exists. 

I have tried installing systemd with:

`apt-get install systemd libpam-systemd systemd-ui`

Then `which systemctl` finds systemctl in `16.10`

but `systemctl status ssh` still gives the error `Failed to connect to bus: No such file or directory`

**Questions**

How can systemd and systemctl be activated for use in Ubuntu Docker images?

Why is systemd not active in Ubuntu Docker containers? Is systemd not used in instantiating the container?

I have failed to find any documentation on this topic for Ubuntu / Ubuntu Docker images, only information on the Ubuntu transition from `Upstart` to `systemd`. Is there any documentation giving a full explanation?

Not able to use systemd on ubuntu docker container

Problem
It seems <code>systemd</code> is not active or available in Ubuntu Docker containers.
Setup
I'm running Docker containers from the <code>ubuntu:16.04</code> and <code>ubuntu:16.10</code> images.
Tests
If I execute:
<code>systemctl status ssh</code> in the <code>16,04</code> container
the result is the error <code>Failed to connect to bus: No such file or directory</code>
In the <code>16.10</code> container the error is: <code>bash: systemctl: command not found</code>.
If I do <code>which systemctl</code> systemctl is found in the <code>16.04</code> container but not in the <code>16.10</code> container.
I have spotted that <code>/lib/systemd</code> exists.
I have tried installing systemd with:
<code>apt-get install systemd libpam-systemd systemd-ui</code>
Then <code>which systemctl</code> finds systemctl in <code>16.10</code>
but <code>systemctl status ssh</code> still gives the error <code>Failed to connect to bus: No such file or directory</code>
Questions
How can systemd and systemctl be activated for use in Ubuntu Docker images?
Why is systemd not active in Ubuntu Docker containers? Is systemd not used in instantiating the container?
I have failed to find any documentation on this topic for Ubuntu / Ubuntu Docker images, only information on the Ubuntu transition from <code>Upstart</code> to <code>systemd</code>. Is there any documentation giving a full explanation?

   I put the locale setting codes below into my dockerfile, 

    FROM node:4-onbuild
    
    # Set the locale
    RUN locale-gen en_US.UTF-8
    ENV LANG en_US.UTF-8
    ENV LANGUAGE en_US:en
    ENV LC_ALL en_US.UTF-8

but it gives me the error 

    /bin/sh: 1: locale-gen: not found
    The command &#39;/bin/sh -c locale-gen en_US.UTF-8&#39; returned a non-zero code: 127

any idea? 

docker ubuntu /bin/sh: 1: locale-gen: not found

I have the latest version of pip 8.1.1 on my ubuntu 16.
But I am not able to install any modules via pip as I get this error all the time.

 

    File &quot;/usr/local/bin/pip&quot;, line 5, in &lt;module&gt;
        from pkg_resources import load_entry_point
      File &quot;/usr/lib/python3/dist-packages/pkg_resources/__init__.py&quot;, line 2927, in &lt;module&gt;
        @_call_aside
      File &quot;/usr/lib/python3/dist-packages/pkg_resources/__init__.py&quot;, line 2913, in _call_aside
        f(*args, **kwargs)
      File &quot;/usr/lib/python3/dist-packages/pkg_resources/__init__.py&quot;, line 2940, in _initialize_master_working_set
        working_set = WorkingSet._build_master()
      File &quot;/usr/lib/python3/dist-packages/pkg_resources/__init__.py&quot;, line 635, in _build_master
        ws.require(__requires__)
      File &quot;/usr/lib/python3/dist-packages/pkg_resources/__init__.py&quot;, line 943, in require
        needed = self.resolve(parse_requirements(requirements))
      File &quot;/usr/lib/python3/dist-packages/pkg_resources/__init__.py&quot;, line 829, in resolve
        raise DistributionNotFound(req, requirers)
    pkg_resources.DistributionNotFound: The &#39;pip==7.1.0&#39; distribution was not found and is required by the application

I found a similar [link][1], but not helpful. 


  [1]: https://stackoverflow.com/questions/38587785/pkg-resources-distributionnotfound-the-pip-1-5-4-distribution-was-not-found


The &#39;pip==7.1.0&#39; distribution was not found and is required by the application

I&#39;ve got a Docker container running Ubuntu which I did as follows:

    docker run -it ubuntu /bin/bash

however it doesn&#39;t seem to have `ping`. E.g.

    bash: ping: command not found

Do I need to install that?

Seems a pretty basic command to be missing. I tried `whereis ping` which doesn&#39;t report anything.



Docker - Ubuntu - bash: ping: command not found

I was getting the following error when trying to run `composer update` on a SimpleSAML project.

    - openid/php-openid dev-master requires ext-gmp * -&gt; the requested PHP extension gmp is missing from your system.


Running `sudo apt-get install php5-gmp` did not work and neither did `sudo apt-get install php7-gmp`

How to install GMP for PHP7 on Ubuntu

I am getting error on ubuntu 16.04

&gt; &quot;ERROR: Couldn&#39;t connect to Docker daemon - you might need to run
&gt; `docker-    machine start default`. &quot;

 when i run following command
 

    sudo docker-compose up

Can any one answer ?

Ubuntu 16.04 - &gt; ERROR: Couldn&#39;t connect to Docker daemon - you might need to run `docker-machine start default`

I can&#39;t seem to get MySQL data to persist if I run `$ docker-compose down` with the following `.yml`

    version: &#39;2&#39;
    services:
      # other services

      data:
        container_name: flask_data
        image: mysql:latest
        volumes:
          - /var/lib/mysql
        command: &quot;true&quot;

      mysql:
        container_name: flask_mysql
        restart: always
        image: mysql:latest
        environment:
          MYSQL_ROOT_PASSWORD: &#39;test_pass&#39; # TODO: Change this
          MYSQL_USER: &#39;test&#39;
          MYSQL_PASS: &#39;pass&#39;
        volumes_from:
          - data
        ports:
          - &quot;3306:3306&quot;
    

My understanding is that in my `data` container using `volumes: - /var/lib/mysql` maps it to my local machines directory where mysql stores data to the container and because of this mapping the data should persist even if the containers are destroyed. And the `mysql` container is just a client interface into the db and can see the local directory because of `volumes_from: - data`

Attempted this answer and it did not work. https://stackoverflow.com/questions/34511336/docker-compose-persistent-data-trouble

**EDIT**

Changed my `.yml` as shown below and created a the dir `./data` but now when I run `docker-compose up --build` the `mysql` container wont start throws error saying

      data:
        container_name: flask_data
        image: mysql:latest
        volumes:
          - ./data:/var/lib/mysql
        command: &quot;true&quot;

      mysql:
        container_name: flask_mysql
        restart: always
        image: mysql:latest
        environment:
          MYSQL_ROOT_PASSWORD: &#39;test_pass&#39; # TODO: Change this
          MYSQL_USER: &#39;test&#39;
          MYSQL_PASS: &#39;pass&#39;
        volumes_from:
          - data
        ports:
          - &quot;3306:3306&quot;


    flask_mysql | mysqld: Can&#39;t create/write to file &#39;/var/lib/mysql/is_writable&#39; (Errcode: 13 - Permission denied)
    flask_mysql | 2016-08-26T22:29:21.182144Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
    flask_mysql | 2016-08-26T22:29:21.185392Z 0 [ERROR] --initialize specified but the data directory exists and is not writable. Aborting.

Docker-Compose persistent data MySQL

I have a `Dockerfile` where I copy an existing directory (with content) to the container which works fine:

**Dockerfile**

    FROM php:7.0-apache
    COPY Frontend/ /var/www/html/aw3somevideo/
    COPY Frontend/ /var/www/html/
    
    RUN ls -al /var/www/html
    RUN chown -R www-data:www-data /var/www/html 
    RUN chmod -R 755 /var/www/html 

[![Screenshot of directory listing with docker exec][1]][1]

But when I use a `docker-compose.yml` file there is only the directory `aw3somevideo` and inside `aw3somevideo` there is nothing.

**docker-compose.yml**:

     php:
        build: php/
        volumes:
          - ./Frontend/ :/var/www/html/
          - ./Frontend/index.php :/var/www/html/
        ports:
          - 8100:80

[![Screenshot of empty directory listing][2]][2]

Maybe I do not understand the function of `volumes` and if that&#39;s the case please tell me how to copy my existing files to the container via a `docker-compose.yml` file.


  [1]: http://i.stack.imgur.com/AXF1s.png
  [2]: http://i.stack.imgur.com/TyMEq.png

Copying files to a container with Docker Compose

I&#39;m trying to figure out how to implement docker using docker-compose.yml with 2 databases imported from sql dumps.

    httpd:
        container_name: webserver
        build: ./webserver/
        ports:
            - 80:80
        links:
            - mysql
            - mysql2
        volumes_from:
            - app
    
    mysql:
        container_name: sqlserver
        image: mysql:latest
        ports:
            - 3306:3306
        volumes:
            - ./sqlserver:/docker-entrypoint-initdb.d
        environment:
            MYSQL_ROOT_PASSWORD: root
            MYSQL_DATABASE: dbname1
            MYSQL_USER: dbuser
            MYSQL_PASSWORD: dbpass
    
    mysql2:
        extends: mysql
        container_name: sqlserver2
        environment:
            MYSQL_ROOT_PASSWORD: root
            MYSQL_DATABASE: dbname2
            MYSQL_USER: dbuser
            MYSQL_PASSWORD: dbpass
    
    app:
        container_name: webdata
        image: php:latest
        volumes:
            - ../php:/var/www/html
        command: &quot;true&quot;


The above returns the following:

    Kronos:mybuild avanche$ ./run.sh 
    Creating sqlserver
    Creating webdata
    Creating sqlserver2
    
    ERROR: for mysql2  driver failed programming external connectivity on endpoint sqlserver2 (6cae3dfe7997d3787a8d59a95c1b5164f7431041c1394128c14e5ae8efe647a8): Bind for 0.0.0.0:3306 failed: port is already allocated
    Traceback (most recent call last):
      File &quot;&lt;string&gt;&quot;, line 3, in &lt;module&gt;
      File &quot;compose/cli/main.py&quot;, line 63, in main
    AttributeError: &#39;ProjectError&#39; object has no attribute &#39;msg&#39;
    docker-compose returned -1

Basically, I&#39;m trying to get my whole stack setup in a single docker compose file, create 2 databases and import the respective sql dumps.
Anyone have any suggestions?





docker-compose with multiple databases

`Dockerfile.1` executes multiple `RUN`:

    FROM busybox
    RUN echo This is the A &gt; a
    RUN echo This is the B &gt; b
    RUN echo This is the C &gt; c

`Dockerfile.2` joins them:

    FROM busybox
    RUN echo This is the A &gt; a &amp;&amp;\
        echo This is the B &gt; b &amp;&amp;\
        echo This is the C &gt; c

Each `RUN` creates a layer, so I always assumed that fewer layers is better and thus `Dockerfile.2` is better.

This is obviously true when a `RUN` removes something added by a previous `RUN` (i.e. `yum install nano &amp;&amp; yum clean all`), but in cases where every `RUN` adds something, there are a few points we need to consider:

0. Layers are supposed to just add a diff above the previous one, so if the later layer does not remove something added in a previous one, there should not be much disk space saving advantage between both methods.

0. Layers are pulled in parallel from Docker Hub, so `Dockerfile.1`, although probably slightly bigger, would theoretically get downloaded faster.

0. If adding a 4th sentence (i.e. `echo This is the D &gt; d`) and locally rebuilding, `Dockerfile.1` would build faster thanks to cache, but `Dockerfile.2` would have to run all 4 commands again.

So, the question: **Which is a better way to do a Dockerfile?**

Multiple RUN vs. single chained RUN in Dockerfile, which is better?

I&#39;ve got a repo set up like this:

    /config
       config.json
    /worker-a
       Dockerfile
       &lt;symlink to config.json&gt;
       /code
    /worker-b
       Dockerfile
       &lt;symlink to config.json&gt;
       /code

However, building the images fails, because Docker can&#39;t handle the symlinks. I should mention my project is far more complicated than this, so restructuring directories isn&#39;t a great option. How do I deal with this situation?

Docker and symlinks

I want systemd to start a script and retry a maximum of 5 times, 30s apart.
Reading the systemd.service manual and searching the Internet didn&#39;t produce any obvious answers.

How to set up a systemd service to retry 5 times on a cycle of 30 seconds

I am using a systemd service which calls a process when it&#39;s been &quot;started&quot; (e.g. `systemctl start test.service`). As per the design, the process stays for ever in a loop, we are able to see process existence using &#39;ps&#39; command. We have also seen that the process is getting killed (as intended) for `systemctl stop` command. 
However our requirement is, we want to do some safe shutdown operations from within the process before it gets killed. But I am not sure how to detect a systemd stop operation from within the process. 

Does a `systemctl stop test.service` command send `SIGKILL` or `SIGTERM` signal to kill the process? How can I detect a `systemctl stop` operation from within a process? 

How systemd stop command actually works

I am having a service that depends on Cassandra coming up gracefully and the cluster being up and ready.

To ensure that the dependency order is met, I have the following unit file 

    [Unit]
    Requires=cassandra.service
    After=cassandra.service
    
    [Service]
    Environment=JAVA_HOME=/usr/java/jre
    ExecStart=@bringup.instance.path@/webapps/bringup-app/bin/bringup
    TimeoutStartSec=0
    ExecStop=
    PIDFile=@bringup.instance.path@/logs/bringup.pid
    Restart=always
    
    [Install]
    WantedBy=multi-user.target

How do I ensure that the bringup-app process waits for 30 seconds before it attempts to start up?  Currently although it is started after Cassandra, I have noticed that the Cassandra cluster is not up yet and hence any attempt from the bringup-app to connect to Cassandra as part of startup fails. 

I therefore want to add a delay. Is that possible via the unit file?

How to ensure that there is a delay before a service is started in systemd?

I&#39;m trying to set up a simple systemd timer to run a bash script every day at midnight.

```systemctl --user status backup.service``` fails and logs the following:

    backup.service: Failed at step EXEC spawning /home/user/.scripts/backup.sh: No such file or directory.

    backup.service: Main process exited, code=exited, status=203/EXEC
    Failed to start backup.
    backup.service: Unit entered failed state.
    backup.service: Failed with result &#39;exit-code&#39;.

I&#39;m lost, since the files and directories exist. The script is executable and, just to check, I&#39;ve even set permissions to 777.

Some background:

The ```backup.timer``` and ```backup.service``` unit files are located in ```/home/user/.config/systemd/user```.

```backup.timer``` is loaded and active, and currently waiting for midnight.

Here&#39;s what it looks like:

    [Unit]
    Description=Runs backup at 0000

    [Timer]
    OnCalendar=daily
    Unit=backup.service

    [Install]
    WantedBy=multi-user.target

Here&#39;s ```backup.service```:

    [Unit]
    Description=backup

    [Service]
    Type=oneshot
    ExecStart=/home/user/.scripts/backup.sh

    [Install]
    WantedBy=multi-user.target

And lastly, this is a paraphrase of ```backup.sh```:
    
    #!/usr/env/bin bash

    rsync -a --delete --quiet /home/user/directory/ /mnt/drive/directory-backup/

The script runs fine if I execute it myself.

Not sure if it matters, but I use ```fish``` as my shell (started from .bashrc).

I&#39;m happy to post the full script if that&#39;s helpful.

Fixing a systemd service 203/EXEC failure (no such file or directory)

Is it possible to create service with the same script started with different input parameters?

Example:

    [Unit]
    Description=script description
    
    [Service]
    Type=simple
    ExecStart=/script.py parameters1
    ExecStart=/script.py parameters2
    Restart=on-failure
    
    [Install]
    WantedBy=multi-user.target

Is it possible? 

Will it be launched in serial-mode? Or in two different process?

Systemd with multiple execStart

I have installed ubuntu 16.04 server. Mysql server was installed by default in it. When I am trying to access the mysql with `mysql -u root -p`, I am unable to log in to mysql because I dont have the password. Is there any default password?

I have also tried with `--skip-grant-tables`, even this does not work. Even trying to log in with just `mysql -u root` is a failure.


Default password of mysql in ubuntu server 16.04

I am trying to deploy a docker configuration with images on a private docker registry.

Now, every time I execute `docker login registry.example.com`, I get the following error message:

&gt; error getting credentials - err: exit status 1, out: `Cannot autolaunch D-Bus without X11 $DISPLAY`

The only solution I found for non-MacOS users was to run `export $(dbus-launch)` first, but that did not change anything.

I am running Ubuntu Server and tried with both the Ubuntu Docker package and the Docker-CE package.

How can I log in without an X11 session?

docker login fails on a server with no X11 installed

I always run my Apache server in this way:

    sudo service apache2 start

But in many guides I saw commands like this:

    sudo systemctl start apache2

Can somebody shortly write the difference between these commands and give me advice about what command I should use in everyday work?

Difference between Systemctl and service command

Hi I&#39;m trying to see the status of my apache services on my Mac. I tried the command 

    sudo service httpd status

but command not found

I look up in Google and discover `systemctl` so I try that

    sudo man systemctl

and it shows no manual entry for `systemctl`

I noticed that I didn&#39;t see much mac os and only see linux in the websites on Google.

Does the command `systemctl` and `service` exists on linux only and not Mac?

If so, what is the mac version of these command?


Content Type	Original Author	Original Content on Stackoverflow
Question	Duncan Gravill	View Question on Stackoverflow
Solution 1 - Ubuntu	BMitch	View Answer on Stackoverflow

Not able to use systemd on ubuntu docker container

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Angular 2 reload route on param change

Google sign in not working after publishing in play store

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