I'm using an Alpine flavor from iron.io. I want to auto-run a trivial 'blink' script as a service when the Docker image starts. (I want derivative images that use this as a base to not know/care about this service--it'd just be "inherited" and run.) I was using S6 for this, and that works well, but wanted to see if something already built into Alpine would work out-of-the-box.
My Dockerfile:
FROM iron/scala
ADD blinkin /bin/
ADD blink /etc/init.d/
RUN rc-update add blink default
And my service script:
#!/sbin/openrc-run
command="/bin/blinkin"
depend()
{
need localmount
}
The /bin/blinkin script:
#!/bin/bash
for I in $(seq 1 5);
do
echo "BLINK!"
sleep 1
done
So I build the Docker image and run it. I see no output (BLINK!...) My script is in /bin and I can run it, and that works. My blink script is in /etc/init.d and symlinked to /etc/runlevels/default. So everything looks ok, but it doesn't seem as anything has run.
If I try: 'rc-service blink start' I see no "BLINK!" outbut, but do get this:
* WARNING: blink is already starting
What am I doing wrong?
You may find my dockerfy utility useful starting services, pre-running initialization commands before the primary command starts. See https://github.com/markriggins/dockerfy
For example:
RUN wget https://github.com/markriggins/dockerfy/releases/download/0.2.4/dockerfy-linux-amd64-0.2.4.tar.gz; \
tar -C /usr/local/bin -xvzf dockerfy-linux-amd64-*tar.gz; \
rm dockerfy-linux-amd64-*tar.gz;
ENTRYPOINT dockerfy
COMMAND --start bash -c "while true; do echo BLINK; sleep 1; done" -- \
--reap -- \
nginx
Would run a bash script as a service, echoing BLINK every second, while the primary command nginx runs. If nginx exits, then the BLINK service will automatically be stopped.
As an added benefit, any zombie processes left over by nginx will be automatically cleaned up.
You can also tail log files such as /var/log/nginx/error.log to stderr, edit nginx's configuration prior to startup and much more
Related
I have a dockerfile image based on ubuntu. Iam trying to make a bash script run each day but the cron never runs. When the container is running, i check if cron is running and it is. the bash script works perfectly and the crontab command is well copied inside the container. i can't seem to find where the problem is coming from.
Here is the Dockerfile:
FROM snipe/snipe-it:latest
ENV TZ=America/Toronto
RUN apt-get update \
&& apt-get install awscli -y \
&& apt-get clean \
&& apt-get install cron -y \
&& rm -rf /var/lib/apt/lists/*
RUN mkdir /var/www/html/backups_scripts /var/www/html/config/scripts
COPY config/crontab.txt /var/www/html/backups_scripts
RUN /usr/bin/crontab /var/www/html/backups_scripts/crontab.txt
COPY config/scripts/backups.sh /var/www/html/config/scripts
CMD ["cron","-f"]
The last command CMD doesn't work. And as soon as i remove the cmd command i get this message when i check the cron task inside the container:
root#fcfb6052274a:/var/www/html# /etc/init.d/cron status
* cron is not running
Even if i start the cron process before the crontab, the crontab is still not launched
This dockerfile is called by a docker swarm file (compose file type). Maybe the cron must be activated with the compose file.
How can i tackle this problem ??? Thank you
You need to approach this differently, as you have to remember that container images and containers are not virtual machines. They're a single process that starts and is maintained through its lifecycle. As such, background processes (like cron) don't exist in a container.
What I've seen most people do is have the container just execute whatever you're looking for it to do on a job like do_the_thing.sh and then using the docker run command on on the host machine to call it via cron.
So for sake of argument, let's say you had an image called myrepo/task with a default entrypoint of do_the_thing.sh
On the host, you could add an entry to crontab:
# m h dom mon dow user command
0 */2 * * * root docker run --rm myrepo/task
Then it's down to a question of design. If the task needs files, you can pass them down via volume. If it needs to put something somewhere when it's done, maybe look at blob storage.
I think this question is a duplicate, with a detailed response with lots of upvotes here. I followed the top-most dockerfile example without issues.
Your CMD running cron in the foreground isn't the problem. I ran a quick version of your docker file and exec'ing into the container I could confirm cron was running. Recommend checking how your cron entries in the crontab file are re-directing their output.
Expanding on one of the other answers here a container is actually a lot like a virtual machine, and often they do run many processes concurrently. If you happen to have any other containers running you might be able to see this most easily by running docker stats and looking at the PID column.
Also, easy to examine interactively yourself like this:
$ # Create a simple ubuntu running container named my-ubuntu
$ docker run -it -h my-ubuntu ubuntu
root#my-ubuntu$ ps aw # Shows bash and ps processes running.
root#my-ubuntu$ # Launch a ten minute sleep in the background.
root#my-ubuntu$ sleep 600 &
root#my-ubuntu$ ps aw # Now shows sleep also running.
I tried to dockerize weblogic server. Now I am facing a issue with Starting node manager after server is started inside the docker container. My docker file as below.
FROM oracle/weblogic:12.1.3-generic
ENV JAVA_OPTIONS="${JAVA_OPTIONS} -
Dweblogic.nodemanager.SecureListener=false" \
ADMIN_PORT="7001" \
ADMIN_HOST="localhost"
USER oracle
COPY dockerfiles/keyStore/keystore_ss.jks /u01/oracle/keystore/
COPY dockerfiles/patch/* /u01/oracle/patch/
COPY dockerfiles/local_domainScripts /u01/oracle/local_domainScripts/
COPY dockerfiles/scripts/* /u01/oracle/
COPY dockerfiles/applicationFiles/ /u01/oracle/applicationFiles/
USER root
RUN yum install -y procps
RUN chmod +x startWeblogic.sh
USER oracle
RUN /u01/oracle/wlst /u01/oracle/local_domainScripts/config.py
RUN nohup bash -c "/u01/oracle/user_projects/domains/local_domain/bin/startNodeManager.sh &" && sleep 4
CMD ["/u01/oracle/user_projects/domains/local_domain/startWebLogic.sh"]
This will create weblogic server instance. I want to start node manager after this server is started.
Run command:
docker run -d --name wls_local_domain --network=host --hostname localhost -p 7001:7001 test-docker:0-SNAPSHOT
When ./startNodeManager.sh is executed inside the container that will start the node manager. To start the node manager, weblogic server need to be started first.
I want to this using bash script. I tried this one but it didn't help
github link
You can't (usefully) RUN a background process. That Dockerfile command launches an intermediate container executing the RUN command, saves its filesystem, and exits; there is no process running any more by the time the next Dockerfile command executes.
If this is a commercially maintained image, you might look into whether Oracle has intstructions on how to use it. (From clicking around, none of the samples there start a node manager; is it necessary?)
Best practice is generally to run only one server in a Docker container (and ideally in the foreground and as the container's main process). If that will work and there aren't shared filesystem dependencies, you can split all of this except the final CMD into one base Dockerfile, then have two additional Dockerfiles that just have a FROM line pointing at your mostly-built image and a requested CMD.
If that really won't work then you'll have to fall back to running some init system in your container, typically supervisord.
You need to start the node manager as a background process then start the server. In order to keep alive the docker container while you are running the background processes, you can use the tail command.
This is how I start the node managed and the WebLogic server in my container:
#!/bin/bash
# ------------------------------------------------------------------------------
# start the Node Manager
# ------------------------------------------------------------------------------
function startNodeManager() {
echo "starting the node manager for $MANAGED_SERVER_NAME server..."
"$ORACLE_HOME/user_projects/domains/$DOMAIN_NAME/bin/startNodeManager.sh" &
while ! nc -z "$HOSTNAME" "$NODE_MANAGER_PORT"; do
sleep 0.5
done
echo "node manager is up and ready to receive requests"
}
# ------------------------------------------------------------------------------
# start the WebLogic Admin server
# ------------------------------------------------------------------------------
function startAdminServer() {
echo "starting the $ADMIN_SERVER_NAME server..."
local logHome
logHome="$ORACLE_HOME/user_projects/domains/$DOMAIN_NAME/servers/$ADMIN_SERVER_NAME/logs"
mkdir -p "$logHome"
"$ORACLE_HOME/user_projects/domains/$DOMAIN_NAME/bin/startWebLogic.sh" > "$logHome/$ADMIN_SERVER_NAME.out" 2>&1 &
}
# ------------------------------------------------------------------------------
# main app starts here
# ------------------------------------------------------------------------------
startNodeManager
startAdminServer
# this command keeps alive the docker container
tail -F \
"$ORACLE_HOME/user_projects/domains/$DOMAIN_NAME/servers/$ADMIN_SERVER_NAME/logs/$ADMIN_SERVER_NAME.log" \
"$ORACLE_HOME/user_projects/domains/$DOMAIN_NAME/servers/$ADMIN_SERVER_NAME/logs/$ADMIN_SERVER_NAME.nohup" \
"$ORACLE_HOME/user_projects/domains/$DOMAIN_NAME/servers/$ADMIN_SERVER_NAME/logs/$ADMIN_SERVER_NAME.out"
This is a complete startup script that you can use as an example and improve it. It starts the node manager and the admin server: https://github.com/zappee/docker-images/blob/master/oracle-weblogic/oracle-weblogic-12.2.1.4-admin-server/container-scripts/startup.sh
From here you can download the complete working solution.
I'm using Search Guard plugin to secure an elasticsearch cluster composed of multiple nodes.
Here is my Dockerfile:
#!/bin/sh
FROM docker.elastic.co/elasticsearch/elasticsearch:5.6.3
USER root
# Install search guard
RUN bin/elasticsearch-plugin install --batch com.floragunn:search-guard-5:5.6.3-16 \
&& chmod +x \
plugins/search-guard-5/tools/hash.sh \
plugins/search-guard-5/tools/sgadmin.sh \
bin/init_sg.sh \
&& chown -R elasticsearch:elasticsearch /usr/share/elasticsearch
USER elasticsearch
To initialize SearchGuard (create internal users and assign roles). I need to run the script init_sg.sh after the container startup.
Here is the problem: Unless elasticsearch is running, the script will not initialize any security index.
The script's content is :
sleep 10
plugins/search-guard-5/tools/sgadmin.sh -cd config/ -ts config/truststore.jks -ks config/kirk-keystore.jks -nhnv -icl
Now, I just run the script manually after the container startup but since I'm running it on Kubernetes.. Pods may get killed or fail and get recreated automatically for some reason. In this case, the plugin have to be initialized automatically after the container startup!
So how to accomplish this? Any help or hint would be really appreciated.
The image itself has an entrypoint ENTRYPOINT ["/run/entrypoint.sh"] specified in the Dockerfile. You can replace it by your own script. So for example create a new script, mount it and first call /run/entrypoint.sh and then wait for start of elasticsearch before running your init_sg.sh.
Not sure this will solves your problem, but its worth check my repo'sDockerfile
I have created a simple run.sh file copied to docker image and in the Dockerfile I wrote CMD ["run.sh"]. In the same way define whatever you want in run.sh and write CMD ["run.sh"]. You can find another example like below
Dockerfile
FROM java:8
RUN apt-get update && apt-get install stress-ng -y
ADD target/restapp.jar /restapp.jar
COPY dockerrun.sh /usr/local/bin/dockerrun.sh
RUN chmod +x /usr/local/bin/dockerrun.sh
CMD ["dockerrun.sh"]
dockerrun.sh
#!/bin/sh
java -Dserver.port=8095 -jar /restapp.jar &
hostname="hostname: `hostname`"
nohup stress-ng --vm 4 &
while true; do
sleep 1000
done
This is addressed in the documentation here: https://docs.docker.com/config/containers/multi-service_container/
If one of your processes depends on the main process, then start your helper process FIRST with a script like wait-for-it, then start the main process SECOND and remove the fg %1 line.
#!/bin/bash
# turn on bash's job control
set -m
# Start the primary process and put it in the background
./my_main_process &
# Start the helper process
./my_helper_process
# the my_helper_process might need to know how to wait on the
# primary process to start before it does its work and returns
# now we bring the primary process back into the foreground
# and leave it there
fg %1
I was trying to solve the exact problem. Here's the approach that worked for me.
Create a separate shell script that checks for ES status, and only start initialization of SG when ES is ready:
Shell Script
#!/bin/sh
echo ">>>> Right before SG initialization <<<<"
# use while loop to check if elasticsearch is running
while true
do
netstat -uplnt | grep :9300 | grep LISTEN > /dev/null
verifier=$?
if [ 0 = $verifier ]
then
echo "Running search guard plugin initialization"
/elasticsearch/plugins/search-guard-6/tools/sgadmin.sh -h 0.0.0.0 -cd plugins/search-guard-6/sgconfig -icl -key config/client.key -cert config/client.pem -cacert config/root-ca.pem -nhnv
break
else
echo "ES is not running yet"
sleep 5
fi
done
Install script in Dockerfile
You will need to install the script in container so it's accessible after it starts.
COPY sginit.sh /
RUN chmod +x /sginit.sh
Update entrypoint script
You will need to edit the entrypoint script or run script of your ES image. So that it starts the sginit.sh in the background BEFORE starting ES process.
# Run sginit in background waiting for ES to start
/sginit.sh &
This way the sginit.sh will start in the background, and will only initialize SG after ES is started.
The reason to have this sginit.sh script starts before ES in the background is so that it's not blocking ES from starting. The same logic applies if you put it after starting of ES, it will never run unless you put the starting of ES in the background.
I would suggest to put the CMD in you docker file to execute the script when the container start
FROM debian
RUN apt-get update && apt-get install -y nano && apt-get clean
EXPOSE 8484
CMD ["/bin/bash", "/opt/your_app/init.sh"]
There is other way , but before using this look at your requirement,
ENTRYPOINT "put your code here" && /bin/bash
#exemple ENTRYPOINT service nginx start && service ssh start &&/bin/bash "use && to separate your code"
You can also use wait-for-it script. It will wait on the availability of a host and TCP port. It is useful for synchronizing the spin-up of interdependent services and works like a charm with containers. It does not have any external dependencies so you can just run it as an RUN command without doing anything else.
A Dockerfile example based on this thread:
FROM elasticsearch
# Make elasticsearch write data to a folder that is not declared as a volume in elasticsearchs' official dockerfile.
RUN mkdir /data && chown -R elasticsearch:elasticsearch /data && echo 'es.path.data: /data' >> config/elasticsearch.yml && echo 'path.data: /data' >> config/elasticsearch.yml
# Download wait-for-it
ADD https://raw.githubusercontent.com/vishnubob/wait-for-it/e1f115e4ca285c3c24e847c4dd4be955e0ed51c2/wait-for-it.sh /utils/wait-for-it.sh
# Copy the files you may need and your insert script
# Insert data into elasticsearch
RUN /docker-entrypoint.sh elasticsearch -p /tmp/epid & /bin/bash /utils/wait-for-it.sh -t 0 localhost:9200 -- path/to/insert/script.sh; kill $(cat /tmp/epid) && wait $(cat /tmp/epid); exit 0;
I have build a Docker image and afterwards run a container using Docker Compose. The following command will do the job for me:
docker-compose up -d
I have restarted the PC and now I want to start the previous container that I've created before. So I have tried the following command:
$ docker-compose start
Starting php-apache ... done
Apparently it works but it doesn't as per the output for the following command:
$ docker-compose ps
Name Command State Ports
---------------------------------------------------------------------------
php55devwork_php-apache_1 /bin/sh -c bash -C '/usr/l ... Exit 0
For sure something is wrong and I am trying to find out what.
How do I find why the command is failing?
Is there any place where I could see a log file or something that help me to identify and fix the error?
Here is the repository if you want to give it a try.
Update
If I remove the container: docker rm <container-id> and recreate it by running docker-compose up -d --build it works again.
Update #1
I am not able to see such weird characters:
This is what helped me to resolve this issue:
Under one of your services in the docker-compose yaml file, type in the following:
tty: true so it'll look like
version: '3'
services:
web:
tty: true
Hopefully this helps someone; thumps up if it helps you :)
I took a look into your Docker github and setup_php_settings
on line (line n. 27) there is source /etc/apache2/envvars && exec /usr/sbin/apache2 -DFOREGROUND
and that runs apache2 on foreground so it shouldn't exit with status code 0.
But it seems to me like your setup_php_settings contains some weird character (when I run your image with compose)
(original is one on right side) weird character
I have changed it to new lines and it worked for me. Let us know if it helped.
If you want to debug your docker container you can run it without entrypoint like:
docker run -it yourImage bash
-- AFTER some investigation:
There were still some errors when I restart docker container - like in your case stopped container and start after reboot. There were problems: symbolic links already exist and apache2 has grumpy PID so we need to do something like in oficial php docker
This is full setup_php_settings worked for me after container restart.
#!/bin/bash -x
set -e
PHP_ERROR_REPORTING=${PHP_ERROR_REPORTING:-"E_ALL & ~E_DEPRECATED & ~E_NOTICE"}
sed -ri 's/^display_errors\s*=\s*Off/display_errors = On/g' /etc/php5/apache2/php.ini
sed -ri 's/^display_errors\s*=\s*Off/display_errors = On/g' /etc/php5/cli/php.ini
sed -ri "s/^error_reporting\s*=.*$//g" /etc/php5/apache2/php.ini
sed -ri "s/^error_reporting\s*=.*$//g" /etc/php5/cli/php.ini
echo "error_reporting = $PHP_ERROR_REPORTING" >> /etc/php5/apache2/php.ini
echo "error_reporting = $PHP_ERROR_REPORTING" >> /etc/php5/cli/php.ini
mkdir -p /data/tmp/php/uploads
mkdir -p /data/tmp/php/sessions
mkdir -p /data/tmp/php/xdebug
chown -R www-data:www-data /data/tmp/php*
ln -sf /etc/php5/mods-available/zz-php.ini /etc/php5/apache2/conf.d/zz-php.ini
ln -sf /etc/php5/mods-available/zz-php-directories.ini /etc/php5/apache2/conf.d/zz-php-directories.ini
# Add symbolic link to get Zend out of the current install dir
ln -sf /usr/share/php/libzend-framework-php/Zend/ /usr/share/php/Zend
a2enmod rewrite
php5enmod mcrypt
# Apache gets grumpy about PID files pre-existing
: "${APACHE_PID_FILE:=${APACHE_RUN_DIR:=/var/run/apache2}/apache2.pid}"
rm -f "$APACHE_PID_FILE"
source /etc/apache2/envvars && exec /usr/sbin/apache2 -DFOREGROUND "$#"
You can check logs with docker compose logs.
Looking through your repo, you have
ENTRYPOINT bash -C '/usr/local/bin/setup_php_settings';'bash'
which, without an interactive session, bash will exit immediately (with an exit code 0) after reading the end of file on stdin.
Normally getting an exit 0 should be a reason to celebrate, as it indicates that your command has ended successfully (http://www.tldp.org/LDP/abs/html/exit-status.html).
Having had a look at your Dockerfile it looks like, your just invoking bash in your entry point which then for sure will exit (as it is non blocking). In order to serve some data, you should rather be calling php (which is a blocking operation that keeps the container up), like done in the official docker files for php (see the CMD ["php", "-a"] at https://github.com/docker-library/php/blob/1c56325a69718a3e3cf76179e75d070b7e23da62/5.6/Dockerfile)
I am trying to do a syntax check on an upstart script using init-checkconf. However when I run it, it returns ERROR: version of /sbin/initctl too old.
I have no idea what to do, I have tried reinstalling upstart but nothing changes. This is being run from within a docker container (ubuntu:14.04) which might have something to do with it.
I just ran into the same issue.
Looking in the container:
root#puppet-master:/# cat /sbin/initctl
#!/bin/sh
exit 0
I haven't tested it completly yet, but I added the following to my Dockerfile:
# Fix upstart
RUN rm -rf /sbin/initctl && ln -s /sbin/initctl.distrib /sbin/initctl
I thought this link explained it pretty good:
When your Docker container starts, only the CMD command is run. The only processes that will be running inside the container is the CMD command, and all processes that it spawns. That's why all kinds of important system services are not run automatically – you have to run them yourself.
Digging around some more, I found an official Ubuntu image containing a working version of upstart:
https://registry.hub.docker.com/_/ubuntu-upstart/