How to install/enable or configure telnet to docker container for elk

General Discussions
1

This is the Dockerfile

FROM docker.elastic.co/beats/filebeat:7.8.0
RUN apt-get update && apt-get install -y telnet && rm -rf /var/lib/apt/lists/*
COPY ./filebeat.docker.yml /usr/share/filebeat/filebeat.yml

But unable to execute the second line… I tried with other filebeat:7.17.3 version as well but it gives the same error.
This is the error

[+] Building 0.7s (6/7)                                                                          docker:default
 => [internal] load build definition from Dockerfile                                                       0.1s
 => => transferring dockerfile: 222B                                                                       0.0s
 => [internal] load .dockerignore                                                                          0.1s
 => => transferring context: 2B                                                                            0.0s
 => [internal] load metadata for docker.elastic.co/beats/filebeat:7.8.0                                    0.0s
 => [1/3] FROM docker.elastic.co/beats/filebeat:7.8.0                                                      0.2s
 => [internal] load build context                                                                          0.1s
 => => transferring context: 464B                                                                          0.0s
 => ERROR [2/3] RUN apt-get update && apt-get install -y telnet && rm -rf /var/lib/apt/lists/*             0.4s
------
 > [2/3] RUN apt-get update && apt-get install -y telnet && rm -rf /var/lib/apt/lists/*:
0.375 /bin/sh: apt-get: command not found
------
Dockerfile:2
--------------------
   1 |     FROM docker.elastic.co/beats/filebeat:7.8.0
   2 | >>> RUN apt-get update && apt-get install -y telnet && rm -rf /var/lib/apt/lists/*
   3 |     COPY ./filebeat.docker.yml /usr/share/filebeat/filebeat.yml
   4 |
--------------------
ERROR: failed to solve: process "/bin/sh -c apt-get update && apt-get install -y telnet && rm -rf /var/lib/apt/lists/*" did not complete successfully: exit code: 127

Could somebody suggest me a way to resolve this? Tried with apk update as well it also doesn’t seem to work… I’m using ubuntu via wsl…

2

Don’t know what Linux distribution is used for the image, but that command does not work.

Did you try apt update && apt install telnet?

3 
docker run --rm -it docker.elastic.co/beats/filebeat:7.8.0 cat /etc/os-release

NAME="CentOS Linux"
VERSION="7 (Core)"
ID="centos"
ID_LIKE="rhel fedora"
VERSION_ID="7"
PRETTY_NAME="CentOS Linux 7 (Core)"
ANSI_COLOR="0;31"
CPE_NAME="cpe:/o:centos:centos:7"
HOME_URL="https://www.centos.org/"
BUG_REPORT_URL="https://bugs.centos.org/"

CENTOS_MANTISBT_PROJECT="CentOS-7"
CENTOS_MANTISBT_PROJECT_VERSION="7"
REDHAT_SUPPORT_PRODUCT="centos"
REDHAT_SUPPORT_PRODUCT_VERSION="7"

So that’s a centos and you need to use yum to install anything.

You can also find this information in the documentation

Quote:

Docker images for Filebeat are available from the Elastic Docker registry. The base image is centos:7.

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