Question: I have Android layout listed below, but *layout\_marginBottom* is not working - there is no any margin between *myTextView* and *myRecyclerView*. 

Any ideas, what may be wrong with my layout?

```
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:paddingBottom="10dp"
    android:paddingLeft="10dp"
    android:paddingTop="10dp"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" >
    <TextView
        android:id="@+id/myTextView"
        android:text="*** Descritpion text"
        app:layout_constraintWidth_default="spread"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintBottom_toTopOf="@+id/myRecyclerView"
        android:layout_marginBottom="300dp" />
    <android.support.v7.widget.RecyclerView
        android:id="@+id/myRecyclerView"
        app:layout_constraintTop_toBottomOf="@+id/myTextView"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintHorizontal_bias="0"
        app:layout_constraintVertical_bias="0"
        app:layout_constraintWidth_default="spread"
        app:layout_constraintHeight_default="wrap"
        android:layout_width="0dp"
        android:layout_height="0dp" />
</android.support.constraint.ConstraintLayout>

```

Answer: 
To understand your question correctly, do you meant to say telnet is not found inside the running container? If not then you can install if while building the image itself.
Why you need telnet to other container?
if you want to copy files from one container to another container then you can use 

`docker cp <containerid>:<path/to/copy> <conatinerid>:<path/to/copy>`

Docker container is like lightweight os that has minimum but necessary requirements 
and telnet is definitely not one of them but still if you want telnet in container and you are using ubuntu image you can install telnet in container with 

`apt-get update && apt-get install telnet`

And if you are using another image you can include telnet in a docker file and from that image you can use telnet into container.

Sorry for writing this in answer. Not having reputation for comment 
but i hope you can understand.