I currently have a cronjob that creates a backup of a postgres db in ansible
- name: Create a cron job to export database.
become_user: postgres
cron:
name: "Export database"
minute: "*/2"
job: "pg_dump -U postgres -W -F t db_name > db_backup-$(date +%Y-%m-%d-%H.%M.%S).tar"
I want to run a gsutil cp command in the same job that then uploads this backup to a storage location in GCP.
I understand that with a cronjob you would simply separate the two jobs with && however I'm not sure how this would work in ansible.
Any pointers would be great, thank you!
What you put in the job attribute will end up in the crontab. (You can check this with crontab -l on the machine).
So you can do everything in ansible, you could do on the crontab directly, including chaining multiple commands separated by && or ;.
If you have a very long line here, I'd suggest to write a script and have cron execute that for readability reasons.
Related
How can I delete or clear all the cron job that I made previously and just run new cron job that I assigned? I'm using crontab -r but it just clear in the crontab display, but it still runs that cron job and the previous cron job that I have already deleted by using that code.
After I clear cron job using crontab -r, I run crontab -l and it shows this output.
No crontab for trygcp
Use this command,
crontab -e
to access crontab, in there you can deleted specific line or job you created.
About the output you are getting, that only means there is no crontab created under the username trygcp
What you can do is this:
crontab -u [username] -e
Where:
-u define user
-e edit user's crontab
This command will create a crontab under your username, but remember you must have root privilege for you to do this.
I can install a new cron job using crontab command.
For example,
crontab -e
0 0 * * * root rdate -s time.bora.net && clock -w > /dev/null 2>&1
Now I have 100 machines in my cluster, I want to install the above cron task in all of the machines.
How to distribute cron jobs to the cluster machines?
Thanks,
Method 1: Ansible
Ansible can distribute machine configuration to remote machines. Please refer to:
https://www.ansible.com/
Method 2: Distributed Cron
You can use distribted cron to assign cron job. It has a master node and you can config your job easily and monitor the running result.
https://github.com/shunfei/cronsun
crontab is stored /var/spool/cron/(username)
so, write your own cron jobs and distribute that location after acquire root permission.
but if other user edit the crontab at the same time, you can never be sure when it will get changed.
below links help you
https://ubuntuforums.org/showthread.php?t=2173811
https://forums.linuxmint.com/viewtopic.php?t=144841
https://serverfault.com/questions/347318/is-it-bad-to-edit-cron-file-manually
Ansible already has a cron module:
https://docs.ansible.com/ansible/2.7/modules/cron_module.html
I have a LAMP container with supervisor.
I add a simple cron
* * * * * root /bin/date >> /var/log/cron.log
from my Dockerfile
ADD ./crons/test /etc/cron.d/test
RUN chmod 0777 /etc/cron.d/test
I start cron via supervisor with a supervisor-cron.conf like this:
[program:cron]
command=/bin/bash -c "cron -f"
numprocs=1
autostart=true
autorestart=true
startretries=2
Cron starts fine and stays up and running. The strange thing is that no cronjob is running automatically [as it should] but when I execute docker exec lamp crontab /etc/cron.d/test the cron job starts and works as expected.
Am I missing something? Everywhere I have read that cron jobs are executed automatically by cron.
I solved it.
I tried both setting them up in /etc/crontab and /etc/cron.d/ .
Cron didn’t auto-start the cron jobs .
However, when I run docker exec lamp crontab /etc/cron.d/my_cronjob_file all played nice. This made me suspicious , and then I read this . So, after adding my_cronjob_file in the container [in the dockerfile] I added RUN crontab /etc/cron.d/my_cronjob_file . This essentially ‘installs’ the cronjob to the crontab table. [I don’t know the internals of cron/tab but that’s the gist I understood.] .
After that , the cron service comes up by supervisor and the cronjob runs like a charm.
This can be solved with the bash file, due to the layered architecture of the Docker, cron service doesn't get initiated with RUN/CMD/ENTRYPOINT commands.
Simply add a bash file which will initiate the cron and other services (if required)
DockerFile
FROM gradle:6.5.1-jdk11 AS build
# apt
RUN apt-get update
RUN apt-get -y install cron
# Setup cron to run every minute to print (you can add/update your cron here)
RUN touch /var/log/cron-1.log
RUN (crontab -l ; echo "* * * * * echo testing cron.... >> /var/log/cron-1.log 2>&1") | crontab
# entrypoint.sh
RUN chmod +x entrypoint.sh
CMD ["bash","entrypoint.sh"]
entrypoint.sh
#!/bin/sh
service cron start & tail -f /var/log/cron-2.log
If any other service is also required to run along with cron then add that service with & in the same command, for example: /opt/wildfly/bin/standalone.sh & service cron start & tail -f /var/log/cron-2.log
Once you will get into the docker container there you can see that testing cron.... will be getting printed every minute in file: /var/log/cron-1.log
I've always used cpanel to set up con jobs but I don't have cpanel now.
So I added a PHP file in the cron.hourly but I want to be sure it will run.
There must be some way to do this. Like a command that lists all the cron jobs that exist?
I am on Debian 7 64 bit.
If you use crontab -e the crontab job will be syntax-checked
If you are just editing /etc/crontab or /etc/cron.*/* there is no automatic checking
nothing will check the code of your job will actually run successfully.
To list all cron jobs for a user:
crontab -u <user> -l
To list all cron jobs for root:
crontab -l
I'm trying to make cron jobs or task schduler working, but I can not figure out why my script is not taken in consideration.
I'm trying to simply archive a folder with:
tar -cvf /volume1/NetBackup/Backups/Monday.tgz /volume1/NetBackup/Backups/ns3268116.ovh.net/
Each time the script starts working but cannot achieve the work. Either with task scheduler or crontab, a file Monday.tgz is created in folder /volume1/NetBackup/Backups/, but this file is only 1024 bytes.
Synology Cron is really fussy.
Here are my own personal notes for Synology DS413j, DSM 5.2:
Hand edit /etc/crontab as root, crontab -e isn't available
Ensure you use tabs not spaces to separate the columns
Your crontab changes may not survive a reboot if there are syntax problems
The who column in crontab may not be reliable. Use root in the who column and /bin/su -c '<command>' <username> to run as another other user
remember that it uses ash not bash so check for bashisms, e.g use >> /path/to/logfile 2>&1' not&>> /path/to/logfile`
It doesn't support 'MAILTO='
you need to restart crond synoservicectl --reload crond for the new crontab to take effect
You may try adding some diagnostics to it. For instance:
Add MAILTO into the crontab file (on top of crontab -e) to receive cron errors by email:
MAILTO=username#domain.com
Redirect output of your tar command to the file:
your command > ~/log.txt 2>&1
Check cron log and look for anomalies. For instance (it may depend on your configuration):
/var/log/cron.log
You may also try searching through /var/log/messages at the time of your cron job.
Is volume1 a resource on remote host? If yes, it is worth checking this part of the system.
I agree about the really nagging nature of Crontab on Synology Linux OSs.
I would certainly suggest to create de desired job as a .sh shell script and call it via CRON task inserted by using the GUI, as suggested here.
As for today (March 2017) is the best method I have found, since working with crontab via CLI is nearly a pain.