Docker container connecting to host service on Windows

docker run -d -p 80:80 --name webserver nginx
docker ps

CONTAINER ID   IMAGE     COMMAND                  CREATED          STATUS          PORTS                NAMES
2733688156aa   nginx     "/docker-entrypoint.…"   14 seconds ago   Up 13 seconds   0.0.0.0:80->80/tcp   webserver

on my windows host I have a Spring Boot application running at port 10090:

netstat -an | grep 10090
  TCP    0.0.0.0:10090          0.0.0.0:0              LISTENING
  TCP    [::]:10090             [::]:0                 LISTENING
  TCP    [::1]:53110            [::1]:10090            TIME_WAIT
  TCP    [::1]:53123            [::1]:10090            TIME_WAIT
  TCP    [::1]:53126            [::1]:10090            TIME_WAIT

and I can also see the nginx container

netstat -an | grep 80
  TCP    0.0.0.0:80             0.0.0.0:0              LISTENING
  TCP    [::]:80                [::]:0                 LISTENING
  TCP    [::1]:80               [::]:0                 LISTENING

If in browser you type "localhost" you should get nginx welcome page (at port 80, default)

Now log into container:
docker exec -it webserver sh

from the container you can connect to
curl host.docker.internal
curl host.docker.internal:10090
they both work, because they "resolve to the internal IP address used by the host"
On my Windows host, if I type "ipconfig" I see that I have
Ethernet adapter vEthernet (WSL): 172.28.176.1
Ethernet adapter Ethernet: 192.168.0.248
If I try:
curl 172.28.176.1:10090
curl 192.168.0.248:10090
they both work on both host and container, but the first is a lot more responsive.
This proves that from container you can access a service running on host.

References:

http://man.hubwiz.com/docset/Docker.docset/Contents/Resources/Documents/docs.docker.com/docker-for-windows/networking.html

NB: besides host.docker.internal , also docker.for.win.localhost can be used, but they have different values (which?)

busybox docker image

https://hub.docker.com/_/busybox/

docker pull busybox
docker inspect busybox

if I see in the Config section (don't look at ContainerConfig ) the Cmd is simply "sh"

which means that if I do

kubectl run --restart=Never busybox -it --image=busybox

I simply get a shell.

If I create a pod who executes simply "env"

kubectl run --restart=Never busybox --image=busybox -- env


and then "inspect" it

kubectl get pod busybox -o yaml

I see that the container got the entry:

args:
  - env

and since the "args" are simply appended to the default command defined in the container ("If you define args, but do not define a command, the default command is used with your new arguments.")... it's equivalent to specifying:

command: ["sh", "-c"]
args: ["env"]

don't forget the "-c", otherwise you get "sh: can't open 'env': No such file or directory"


NB: if with "kubectl run" you specify --command

kubectl run busybox --image=busybox --restart=Never --command -- env

then "command" instead of "args" will be generated:

spec:
  containers:
  - command:
    - env
    image: busybox
    name: busybox

This aspect of containers/pods (how to run a command with arguments) is rather confusing and poorly engineered.

Container PID 1

PRICELESS article on PID one, SIGTERM and kill in containers:

https://blog.no42.org/code/docker-java-signals-pid1/

the trick is using "exec java bla" so that java becomes PID 1.


$ kill -l
1) SIGHUP 2) SIGINT 3) SIGQUIT 4) SIGILL 5) SIGTRAP
6) SIGABRT 7) SIGEMT 8) SIGFPE 9) SIGKILL 10) SIGBUS
11) SIGSEGV 12) SIGSYS 13) SIGPIPE 14) SIGALRM 15) SIGTERM
16) SIGURG 17) SIGSTOP 18) SIGTSTP 19) SIGCONT 20) SIGCHLD
21) SIGTTIN 22) SIGTTOU 23) SIGIO 24) SIGXCPU 25) SIGXFSZ
26) SIGVTALRM 27) SIGPROF 28) SIGWINCH 29) SIGPWR 30) SIGUSR1
31) SIGUSR2 32) SIGRTMIN 33) SIGRTMIN+1 34) SIGRTMIN+2 35) SIGRTMIN+3
36) SIGRTMIN+4 37) SIGRTMIN+5 38) SIGRTMIN+6 39) SIGRTMIN+7 40) SIGRTMIN+8
41) SIGRTMIN+9 42) SIGRTMIN+10 43) SIGRTMIN+11 44) SIGRTMIN+12 45) SIGRTMIN+13
46) SIGRTMIN+14 47) SIGRTMIN+15 48) SIGRTMIN+16 49) SIGRTMAX-15 50) SIGRTMAX-14
51) SIGRTMAX-13 52) SIGRTMAX-12 53) SIGRTMAX-11 54) SIGRTMAX-10 55) SIGRTMAX-9
56) SIGRTMAX-8 57) SIGRTMAX-7 58) SIGRTMAX-6 59) SIGRTMAX-5 60) SIGRTMAX-4
61) SIGRTMAX-3 62) SIGRTMAX-2 63) SIGRTMAX-1 64) SIGRTMAX


"The SIGTERM signal is a generic signal used to cause program termination. Unlike SIGKILL, this signal can be blocked, handled, and ignored. It is the normal way to politely ask a program to terminate."


See also https://docs.docker.com/v17.12/engine/reference/run/#specify-an-init-process

"You can use the --init flag to indicate that an init process should be used as the PID 1 in the container. Specifying an init process ensures the usual responsibilities of an init system, such as reaping zombie processes, are performed inside the created container."

https://github.com/krallin/tini "All Tini does is spawn a single child (Tini is meant to be run in a container), and wait for it to exit all the while reaping zombies and performing signal forwarding." "Tini is included in Docker itself"

"A process running as PID 1 inside a container is treated specially by Linux: it ignores any signal with the default action. So, the process will not terminate on SIGINT or SIGTERM unless it is coded to do so."

podman! skopio!

sudo yum install epel-release -y
sudo yum install dnf -y
sudo dnf install -y podman

segmentation fault!

alias docker=podman

funny presentation




https://github.com/containers/conmon

docker cheat sheets

https://github.com/wsargent/docker-cheat-sheet


About "docker inspect". you can inspect a container or an image.


docker inspect $containerid

-> there are 2 places with "Image", one showing the image's sha2, the other the image's name.
If you use the sha2 to identify the image, remember it's truncated to the leftmost 12 digits.

docker image inspect $imagename (or $imagesha2)

here you find the Cmd and Entrypoint`


You can assign a label to image in Dockerfile:
LABEL app=hello-world

and use it to filter:

docker images --filter "label=app=hello-world"


since version 18.6 you can use BuildKit https://docs.docker.com/engine/reference/builder/#label :

without BuildKit:

docker build -t myhw .
Sending build context to Docker daemon  9.728kB
Step 1/3 : FROM busybox:latest
 ---> db8ee88ad75f
Step 2/3 : CMD echo "Hello world date=" `date`
 ---> Using cache
 ---> 22bd2fd85b95
Step 3/3 : LABEL app=hello-world
 ---> Running in 1350a308f4eb
Removing intermediate container 1350a308f4eb
 ---> 7a576b758d86
Successfully built 7a576b758d86
Successfully tagged myhw:latest

export DOCKER_BUILDKIT=1


with BuildKit:

docker build -t myhw .
[+] Building 2.2s (5/5) FINISHED                                                                                                                                                                                   
 => [internal] load .dockerignore                                                                                                                                                                             1.5s
 => => transferring context: 2B                                                                                                                                                                               0.0s
 => [internal] load build definition from Dockerfile                                                                                                                                                          1.2s
 => => transferring dockerfile: 181B                                                                                                                                                                          0.0s
 => [internal] load metadata for docker.io/library/busybox:latest                                                                                                                                             0.0s
 => [1/1] FROM docker.io/library/busybox:latest                                                                                                                                                               0.0s
 => => resolve docker.io/library/busybox:latest                                                                                                                                                               0.0s
 => exporting to image                                                                                                                                                                                        0.0s
 => => exporting layers                                                                                                                                                                                       0.0s
 => => writing image sha256:4ce77b76b309be143c25ad75add6cdf17c282491e2966e6ee32edc40f802b1f4                                                                                                                  0.0s
 => => naming to docker.io/library/myhw     

CMD vs ENTRYPOINT

if you use
ENTRYPOINT echo "pippo "
docker build -t echopippo .
docker run echopippo

it will print "pippo"

if you use also CMD
ENTRYPOINT echo "pippo "
CMD " peppo"

it will still print only "pippo". To append arguments, you must use the JSON array format (i.e. square brackets)

ENTRYPOINT ["echo", "pippo "]
CMD [" peppo"]


this will print "pippo peppo".

If you provide an extra parameter from command line:
docker run echopippo pluto

then CMD is ignored, and the parameter from command line is used:
pippo pluto




Priceless Romin Irani turorial on :

docker volumes: https://rominirani.com/docker-tutorial-series-part-7-data-volumes-93073a1b5b72

Dockerfile: https://rominirani.com/docker-tutorial-series-writing-a-dockerfile-ce5746617cd


Other tutorials here https://github.com/botchagalupe/DockerDo

dockerfile cmd and entrypoint

very confusing, poor design IMHO


Dockerfile:

FROM ubuntu
ENV myname "pierre"
ENTRYPOINT ["/bin/bash", "-c", "echo hello ${myname}"]


docker built -t hello01 .
docker run hello01





FROM ubuntu
ENTRYPOINT ["sleep"]

docker built -t hello02 .
docker run hello02

#this sleep for 5s
docker run hello02 5

#this gives error because parameter is missing
docker run hello02



FROM ubuntu
ENTRYPOINT ["sleep"]
CMD ["5"]


this version uses a default time of 5, if not specified in command line
"docker run hello02" will sleep for 5
"docker run hello02 10" will sleep for 10

CRI-O

https://cri-o.io/

CRI-O = "Container Runtime Interface" "Open Container Initiative"
"a lightweight alternative to using Docker as the runtime for kubernetes"

https://www.quora.com/How-is-CRI-O-different-from-Docker-technology

"The CRI-O Container Engine is a implementation of a CRI (Kubernetes Container Runtime interface) that dedicated to Kubernetes. It implements only the features necessary to implement the CRI. Basically whatever Kubernetes needs. The goal to be as simple as possible and to never ever break Kubernetes. CRI-O is only for running containers in production. It runs OCI containers based on OCI images, which basically says it can run any container image sitting at Docker.io, Quay.IO, or any other container registry. It also launches OCI containers with runc.

Docker has a whole bunch of different technology, but I am guessing you are asking about the Docker daemon. Docker daemon is a general purpose container engine that implements API for launching OCI Container using the same runc that CRI-O uses. Docker daemon supports multiple different orchestrators including the Docker Client, Docker Swarm, Kubernetes, Mesosphere. It also supports everything from playing with containers to building containers.

The team behind CRI-O believes that building containers and developing and playing with containers should be done by different tools than the container engine that is used by Kubernetes. The CRI-O team has developed the Podman and Buildah container engines for developing/playing with containers and building container images.

Since these three tasks are done separately CRI-O can run with much tighter security than is required for building and developing containers."




CRI-O and kubeadm

https://katacoda.com/courses/kubernetes/getting-started-with-kubeadm-crio





What is a "pause" container and a "PID namespace sharing" ? https://www.ianlewis.org/en/almighty-pause-container


What is Weave ? https://www.weave.works/docs/cloud/latest/overview/

What is a Nodeport ? https://kubernetes.io/docs/concepts/services-networking/service/#nodeport

GNOME desktop on Centos 7 docker

https://linuxconfig.org/how-to-install-gui-gnome-on-centos-7-linux-system

open Git Bash

winpty docker run -ti --name centos centos bash
#run all the commands to install GNOME
exit
docker start centos
winpty docker exec -ti centos bash

#uptime gives you the number of days the HOST was up, not the container
uptime

Running Centos on Windows

once you have upgraded to Windows PRO, you can install https://docs.docker.com/docker-for-windows/install/ Docker for Windows

Then open your Git Bash shell and run:

winpty docker run --name centos -i -t -d centos

If the container is stopped, you can simply

docker start centos

and login again:

winpty docker exec -ti centos bash


So you can have a "REAL" Centos on Windows... cool...

Docker broken after upgrade

sudo systemctl start docker
Job for docker.service failed because the control process exited with error code. See "systemctl status docker.service" and "journalctl -xe" for details.


sudo journalctl -xe


Error starting daemon: error initializing graphdriver: /var/lib/docker contains several valid graphdrivers: devicemapper, overlay2; Please cleanup or explicit

sudo vi /etc/docker/daemon.json

append this at the end and before the closed curly brace:

,"storage-driver": "devicemapper"



sudo systemctl reset-failed docker.service
sudo systemctl start docker.service

Nexus repo validates Docker images on production.cloudflare.docker.com

In Nexus logs I find a lot of calls to production.cloudflare.docker.com:



2018-11-05 14:13:43,416+0100 DEBUG [qtp72695066-56] ADV org.sonatype.nexus.httpclient.outbound - https://production.cloudflare.docker.com/registry-v2/docker/registry/v2/blobs/sha256/4f/4fe2ade4980c2dda4fc95858ebb981489baec8c1e4bd282ab1c3560be8ff9bde/data?verify=1541426623-n%2BHbbRXN3Rr4k6Bxofrsv6tRVFw%3D > GET /registry-v2/docker/registry/v2/blobs/sha256/4f/4fe2ade4980c2dda4fc95858ebb981489baec8c1e4bd282ab1c3560be8ff9bde/data?verify=1541426623-n%2BHbbRXN3Rr4k6Bxofrsv6tRVFw%3D HTTP/1.1
2018-11-05 14:13:43,416+0100 DEBUG [qtp72695066-56] ADV org.sonatype.nexus.internal.httpclient.SharedHttpClientConnectionManager - Connection request: [route: {tls}->http://ourproxy:8080->https://production.cloudflare.docker.com:443][total kept alive: 1; route allocated: 0 of 20; total allocated: 3 of 200]
2018-11-05 14:13:43,417+0100 DEBUG [qtp72695066-56] ADV org.sonatype.nexus.internal.httpclient.SharedHttpClientConnectionManager - Connection leased: [id: 18][route: {tls}->http://ourproxy:8080->https://production.cloudflare.docker.com:443][total kept alive: 1; route allocated: 1 of 20; total allocated: 4 of 200]
2018-11-05 14:13:43,475+0100 DEBUG [qtp72695066-4467] ADV org.sonatype.nexus.httpclient.outbound - https://auth.docker.io/token?service=registry.docker.io&scope=repository:library/alpine:pull < HTTP/1.1 200 OK @ 129.8 ms 2018-11-05 14:13:43,475+0100 DEBUG [qtp72695066-4467] ADV org.sonatype.nexus.repository.docker.internal.DockerProxyFacetImpl - Response: HttpResponseProxy{HTTP/1.1 200 OK [Content-Type: application/json, Date: Mon, 05 Nov 2018 13:13:43 GMT, Transfer-Encoding: chunked, Strict-Transport-Security: max-age=31536000, Connection: Keep-Alive] ResponseEntityProxy{[Content-Type: application/json,Chunked: true]}}

we access internet via a Proxy Server ourproxy, which doesn't whitelist production.cloudflare.docker.com

each of them creates a file in $NEXUS_DATA/tmp/docker-content-validation-failures with an "access denied" message from ourproxy

Here https://forums.docker.com/t/corporate-firewall-remote-error-tls-handshake-failure/52965 they say we should also whitelist production.cloudflare.docker.com

I have no idea if the "docker pull" will fail, or if this "validation" can be disabled...




See also https://support.sonatype.com/hc/en-us/articles/115015442847-Whitelisting-Docker-Hub-Hosts-for-Firewalls-and-HTTP-Proxy-Servers

More JIRA on Docker

See also https://www.javamonamour.org/2017/11/jira-on-docker-and-integration-with.html


docker run -d -p 8080:8080 cptactionhank/atlassian-jira:7.7.0


I need to install netstat, but I have no root access (root pw is not given), so I do:

docker exec -ti --user root elastic_agnesi /bin/sh

and I get this strange error:

OCI runtime exec failed: exec failed: container_linux.go:348: starting container process caused "chdir to cwd (\"/var/atlassian/jira\") set in config.json failed: permission denied": unknown


woorkaround:

docker exec -ti elastic_agnesi /bin/sh
chmod 777 .
chmod 777 ..
exit

and try again connecting as root.... I have no idea why, but this time it works....

Then as root do

apt install net-tools

Then I discover that only tcp (not tcp6) ports are available, because the image doesn't support IPv6 : "cat /proc/net/if_inet6" returns nothing.

Now I start my webhook intercepting application with IPv4

java -Djava.net.preferIPv4Stack=true -jar bla.jar

before:

[centos@localhost ~]$ netstat -an | grep 8090
tcp6 0 0 :::8090 :::* LISTEN

after:

[centos@localhost ~]$ netstat -an | grep 8090
tcp 0 0 0.0.0.0:8090 0.0.0.0:* LISTEN

but still curl -X POST http://localhost:8090/greeting is not working... I am giving up and will install JIRA directly on host....

Nexus programmatically create Repositories

Nexus API sucks - big time.

This https://blog.sonatype.com/automated-setup-of-a-repository-manager is a desperate attempt to automate stuff.


git clone https://github.com/sonatype/nexus-book-examples.git
cd ./nexus-book-examples/scripting/complex-script

docker run -d -p 8081:8081 --name nexus sonatype/nexus3:3.10.0
see https://hub.docker.com/r/sonatype/nexus3/tags/

check the logs by
docker exec -ti nexus /bin/bash
more /opt/sonatype/sonatype-work/nexus3/log/nexus.log


rm -rf /home/centos/.groovy/grapes/
rm -rf /home/centos/.m2/repository/



You can easily test your scripts from the Nexus UI (create execute script UI) , and also debut them remotely from Intellij :

https://support.sonatype.com/hc/en-us/articles/115015812727-Nexus-3-Groovy-Script-development-environment-setup

Try running this script:

repository.createMavenHosted('pippo')

it can't be easier!


The RepositoryAPI is available here

https://github.com/sonatype/nexus-public/blob/master/plugins/nexus-script-plugin/src/main/java/org/sonatype/nexus/script/plugin/RepositoryApi.java

Repository createMavenHosted(final String name,
final String blobStoreName,
final boolean strictContentTypeValidation,
final VersionPolicy versionPolicy,
final WritePolicy writePolicy,
final LayoutPolicy layoutPolicy);

example:


repository.createMavenHosted('private-again', 'default', true, org.sonatype.nexus.repository.maven.policy.VersionPolicy.SNAPSHOT, org.sonatype.nexus.repository.storage.WritePolicy.ALLOW_ONCE, org.sonatype.nexus.repository.maven.LayoutPolicy.STRICT)



To list repositories (unfortunately it returns only partial information about the Repository):

curl -X GET --header 'Accept: application/json' 'http://localhost:8081/service/rest/beta/repositories'

[ {
  "name" : "nuget.org-proxy",
  "format" : "nuget",
  "type" : "proxy",
  "url" : "http://localhost:8081/repository/nuget.org-proxy"
}, {
  "name" : "maven-releases",
  "format" : "maven2",
  "type" : "hosted",
  "url" : "http://localhost:8081/repository/maven-releases"
}, {
  "name" : "maven-snapshots",
  "format" : "maven2",
  "type" : "hosted",
  "url" : "http://localhost:8081/repository/maven-snapshots"
}, {
  "name" : "maven-central",
  "format" : "maven2",
  "type" : "proxy",
  "url" : "http://localhost:8081/repository/maven-central"
}, {
  "name" : "nuget-group",
  "format" : "nuget",
  "type" : "group",
  "url" : "http://localhost:8081/repository/nuget-group"
}, {
  "name" : "nuget-hosted",
  "format" : "nuget",
  "type" : "hosted",
  "url" : "http://localhost:8081/repository/nuget-hosted"
}, {
  "name" : "maven-public",
  "format" : "maven2",
  "type" : "group",
  "url" : "http://localhost:8081/repository/maven-public"
} ]

Ref: https://help.sonatype.com/repomanager3/rest-and-integration-api/script-api/writing-scripts about Groovy Scripting in Nexus

Eclipse Linux Tools (Docker Plugin) source code

https://wiki.eclipse.org/Linux_Tools_Project/Git

git clone git://git.eclipse.org/gitroot/linuxtools/org.eclipse.linuxtools.git



jars are installed NOT under the Eclipse installation folder, BUT here

/home/centos/.p2/pool/features/org.eclipse.linuxtools.docker.feature_4.0.0.201806122135
/home/centos/.p2/pool/plugins/org.eclipse.linuxtools.docker.docs_4.0.0.201806122135.jar
/home/centos/.p2/pool/plugins/org.eclipse.linuxtools.docker.core_4.0.0.201806122135.jar
/home/centos/.p2/pool/plugins/org.eclipse.linuxtools.docker.editor_1.0.0.201806122135.jar
/home/centos/.p2/pool/plugins/org.eclipse.linuxtools.docker.ui_4.0.0.201806122135.jar


Here they explain how to submit a bug http://git.eclipse.org/c/linuxtools/org.eclipse.linuxtools.git/about/

Unfortunately there is a bug in org.eclipse.linuxtools.internal.docker.ui.wizards.ContainerCopyTo

@Override
    public boolean performFinish() {
        boolean finished = mainPage.finish();
        if (finished) {
            target = mainPage.getDestination().toOSString();
            sources = mainPage.getFilesToCopy();
        }
        return finished;
    }

If you run Eclipse on Windows, and the docker daemon runs on Linux, the toOSString() formats any path into the Windows format, which is not recognized by Linux. So you can't specify "/var" because it will be turned into "\\var" which obviously fails on Linux.

https://bugs.eclipse.org/bugs/show_bug.cgi?id=539239 bug submitted

building .net applications on a docker image

The pain is that you can't run a Windows docker image on Linux. And Microsoft images with the .net libraries are all Windows.
Like this one https://hub.docker.com/r/compulim/msbuild/

BUT you can build a ubuntu-based docker builder image:

https://medium.com/@hudsonmendes/build-net-4-5-on-linux-in-5-minutes-and-see-what-it-is-like-848ea45fc667


it's available on docker hub as vernetto/ubuntudotnet:1.0

Ref: how to push to docker hub https://ropenscilabs.github.io/r-docker-tutorial/04-Dockerhub.html

how to submit a container to an image and save it as tar https://docs.docker.com/engine/reference/commandline/save/#description

docker latest update fails miserably

sudo journalctl -xe

mkdir /run/containerd/io.containerd.runtime.v2.task/docker/dockerd: file exists: unknown


it seems a bug of the latest (nightly) release.... which was installed automatically by the Centos updates process.


I uninstall everything:

sudo yum remove docker docker-common docker-selinux docker-engine

Then I install

https://docs.docker.com/install/linux/docker-ce/centos/#set-up-the-repository

sudo yum-config-manager --disable docker-ce-edge

sudo yum install docker-ce
sudo systemctl enable docker
systemctl start docker

systemctl status docker.service

Error starting daemon: error initializing graphdriver: /var/lib/docker contains several valid graphdrivers: devicemapper, overlay2; Please cleanup or explicit

sudo vi /usr/lib/systemd/system/docker.service

ExecStart=/usr/bin/dockerd -s=devicemapper -H tcp://0.0.0.0:2375 -H unix:///var/run/docker.sock

sudo systemctl daemon-reload
sudo systemctl start docker

ELK docker

http://elk-docker.readthedocs.io/

you have to adjust permanently the max_map_count parameter:

sysctl -w vm.max_map_count=262144

(sysctl - configure kernel parameters at runtime)

ls /proc/sys/vm to get list of available parameters

sudo vi /etc/sysctl.conf
vm.max_map_count=262144

try starting the container like this:

sudo docker run -p 5601:5601 -p 9200:9200 -p 5044:5044 -it --name elk sebp/elk

if it fails with this error:

waiting for Elasticsearch to be up (30/30)
Couln't start Elasticsearch. Exiting.

try allowing more time:

sudo docker run -e ES_CONNECT_RETRY=300 -p 5601:5601 -p 9200:9200 -p 5044:5044 -it --name elk sebp/elk

(see https://docs.docker.com/engine/reference/commandline/run/#set-environment-variables--e---env---env-file )

then

http://127.0.0.1:5601/app/kibana KIBANA (you have to wait 1 minute for Kibana to come up)

http://127.0.0.1:9200/ Elasticsearch JSON

to create dummy entry:

docker exec -it elk /bin/bash
/opt/logstash/bin/logstash --path.data /tmp/logstash/data -e 'input { stdin { } } output { elasticsearch { hosts => ["localhost"] } }'
this is a dummy entry
this is a dummy entry2
CTRL-C


Kibana logs : less /var/log/kibana/kibana5.log
Elasticsearch logs : less /var/log/elasticsearch/elasticsearch.log
Logstash logs: less /var/log/logstash/logstash-plain.log

tail -f /var/log/elasticsearch/elasticsearch.log /var/log/logstash/logstash-plain.log /var/log/kibana/kibana5.log



docker network create -d bridge elknet


good practical presentation of ELK:

Eclipse for Docker

To install: Help/Eclipse Marketplace, search for Docker Tools, install.
Otherwise, install https://tools.jboss.org/features/dockertools.html "JBoss Tools" and you get also Docker Tools.

Show View / Docker Explorer

you get by default this one:

unix:///var/run/docker.sock

but you can also work with remote docker via TCP with authentication


this view shows ALL your containers (docker ps -a) and images (docker images), with a list of ports and volumes

https://www.eclipse.org/community/eclipse_newsletter/2015/june/article3.php


To enable managing a Docker environment running in your VirtualBox centos image, in VirtualBox enable port forwarding 2376 or 2375, see http://www.javamonamour.org/2017/12/docker-enabling-remote-daemon.html

Eclipse for Docker is a really nice tool! It makes it much easier to work with Docker. However I still believe one should be familiar with the Docker CLI.

Testcontainers, using Docker containers in JUnit tests

Junit sucks, use at least 5.0 or better switch to TestNG (see http://www.baeldung.com/junit-vs-testng for comparison)


https://www.javacodegeeks.com/2018/05/testcontainers-and-spring-boot.html

https://github.com/bijukunjummen/cities

https://www.testcontainers.org/usage.html#maven-dependencies

https://github.com/testcontainers/testcontainers-java-examples

https://github.com/testcontainers/testcontainers-java


https://search.maven.org/#search%7Cga%7C1%7Cg%3A%22org.testcontainers%22


To keep it really minimalistic, I have created a Maven Java project:

<project xmlns="http://maven.apache.org/POM/4.0.0"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 <modelVersion>4.0.0</modelVersion>
 <groupId>org.pierre</groupId>
 <artifactId>testcontainer</artifactId>
 <version>1.0</version>
 <dependencies>
  <dependency>
   <groupId>org.testcontainers</groupId>
   <artifactId>testcontainers</artifactId>
   <version>1.7.3</version>
  </dependency>
  
  <dependency>
   <groupId>org.testcontainers</groupId>
   <artifactId>selenium</artifactId>
   <version>1.7.3</version>
  </dependency>
  
   
  
  <dependency>
   <groupId>org.seleniumhq.selenium</groupId>
   <artifactId>selenium-remote-driver</artifactId>
   <version>2.45.0</version>
  </dependency>
  <dependency>
   <groupId>org.slf4j</groupId>
   <artifactId>slf4j-api</artifactId>
   <version>1.7.7</version>
   <scope>provided</scope>
  </dependency>
  <dependency>
   <groupId>ch.qos.logback</groupId>
   <artifactId>logback-classic</artifactId>
   <version>1.1.2</version>
   <scope>test</scope>
  </dependency>
 </dependencies>

 <properties>
  <maven.compiler.target>1.8</maven.compiler.target>
  <maven.compiler.source>1.8</maven.compiler.source>
 </properties>
</project>

and copied this example

package org.pierre.testcontainer;

import org.junit.Rule;
import org.junit.Test;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.remote.DesiredCapabilities;
import org.openqa.selenium.remote.RemoteWebDriver;
import org.testcontainers.containers.BrowserWebDriverContainer;

import java.io.File;

import static org.rnorth.visibleassertions.VisibleAssertions.assertTrue;
import static org.testcontainers.containers.BrowserWebDriverContainer.VncRecordingMode.RECORD_ALL;


public class SeleniumContainerTest {

    @Rule
    public BrowserWebDriverContainer chrome = new BrowserWebDriverContainer()
                                                    .withDesiredCapabilities(DesiredCapabilities.chrome())
                                                    .withRecordingMode(RECORD_ALL, new File("target"));

    @Test
    public void simplePlainSeleniumTest() {
        RemoteWebDriver driver = chrome.getWebDriver();

        driver.get("https://wikipedia.org");
        WebElement searchInput = driver.findElementByName("search");

        searchInput.sendKeys("Rick Astley");
        searchInput.submit();

        WebElement otherPage = driver.findElementByLinkText("Rickrolling");
        otherPage.click();

        boolean expectedTextFound = driver.findElementsByCssSelector("p")
                .stream()
                .anyMatch(element -> element.getText().contains("meme"));

        assertTrue("The word 'meme' is found on a page about rickrolling", expectedTextFound);
}

}

The first time it failed with a SocketTimeoutException.... the second time it succeeded... I guess simply the Docker container was taking too much time to start.

If I do "docker images" I see richnorth/vnc-recorder and selenium/standalone-chrome-debug. If I do "docker ps -a" I see no trace of containers, probably they are removed at the end of test.


It looks really interesting! Convenient way to prepare a test environment in a fully automated way.

Preparing a Centos VirtualBox with Docker.... putting it all together

sudo vi /etc/sysconfig/network-scripts/ifcfg-enp0s3
add these 3 lines:
ONBOOT=yes
DNS1=8.8.8.8
DNS2=8.8.4.4


sudo reboot now
ping google.com
sudo yum install gcc kernel-devel-$(uname -r)

now you can install VirtualBox Guest Additions (Devices/Insert Guest Additions CD image)

to install DOcker https://docs.docker.com/install/linux/docker-ce/centos/#install-from-a-package

sudo yum check-update
sudo yum install -y yum-utils device-mapper-persistent-data lvm2
sudo yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
sudo yum install docker-ce
sudo systemctl start docker
sudo usermod -aG docker $(whoami)
sudo docker run hello-world

you can now reboot




Some fine tuning on VB:
File/Preferences/Input:
- set Host Key Combination
- disable "auto capture Keyboard"

General/Advanced/Shared Clipboard set to Bidirectional