Set system timezone from node-RED

General
1

Hi,

Im trying to set timezone inside the Docker container from node-RED this way:

image
image642×216 12.9 KB

The idea is to inject timezone so I can easily set system timezone. Im running v4.0.5 on docker.

This method throws an error because the Node-RED user isn’t root, so I can’t modify /etc/localtime .
Any idea how I could work around this?

Thanks!

codeHere 
[{"id":"eecaed65c5c38d92","type":"inject","z":"fbf8a7aab69c85cc","name":"timezone EUROPE CENTRAL","props":[{"p":"payload"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"ln -s /usr/share/zoneinfo/Europe/Madrid /etc/localtime","payloadType":"str","x":192,"y":112,"wires":[["d6e42ee8f919fa9d"]],"icon":"font-awesome/fa-clock-o"},{"id":"631286a30962de4b","type":"exec","z":"fbf8a7aab69c85cc","command":"","addpay":"payload","append":"","useSpawn":"false","timer":"","winHide":false,"oldrc":false,"name":"execTimezone","x":512,"y":128,"wires":[["893ac4a1dba6c1a8"],[],[]]},{"id":"b616b072dfe7098c","type":"inject","z":"fbf8a7aab69c85cc","name":"timezone MEXICO","props":[{"p":"payload"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"ln -s /usr/share/zoneinfo/America/Mexico_City /etc/localtime","payloadType":"str","x":162,"y":152,"wires":[["b1533089fe82692e"]],"icon":"font-awesome/fa-clock-o"},{"id":"15fbd12eee3ea874","type":"debug","z":"fbf8a7aab69c85cc","name":"debug 90","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","statusVal":"","statusType":"auto","x":673,"y":128,"wires":[],"l":false},{"id":"041ab52e33d9f71d","type":"inject","z":"fbf8a7aab69c85cc","name":"timezone CHINA","props":[{"p":"payload"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"ln -s /usr/share/zoneinfo/Asia/Shanghai /etc/localtime","payloadType":"str","x":152,"y":72,"wires":[["74557fbc1d3ab1cc"]],"icon":"font-awesome/fa-clock-o"},{"id":"893ac4a1dba6c1a8","type":"change","z":"fbf8a7aab69c85cc","name":"","rules":[{"t":"set","p":"topic","pt":"msg","to":"RESTART CONTAINER","tot":"str"}],"action":"","property":"","from":"","to":"","reg":false,"x":623,"y":128,"wires":[["15fbd12eee3ea874"]],"icon":"node-red/arrow-in.svg","l":false},{"id":"5391b1db258b29e0","type":"inject","z":"fbf8a7aab69c85cc","name":"timeNow","props":[{"p":"payload"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"","payloadType":"date","x":580,"y":176,"wires":[["15fbd12eee3ea874"]],"icon":"font-awesome/fa-question-circle"},{"id":"d6e42ee8f919fa9d","type":"junction","z":"fbf8a7aab69c85cc","x":384,"y":112,"wires":[["631286a30962de4b"]]},{"id":"b1533089fe82692e","type":"junction","z":"fbf8a7aab69c85cc","x":384,"y":152,"wires":[["631286a30962de4b"]]},{"id":"74557fbc1d3ab1cc","type":"junction","z":"fbf8a7aab69c85cc","x":384,"y":72,"wires":[["631286a30962de4b"]]}]
2

That makes it even more difficult as one of the reasons for using Docker is to keep the system safe from applications trying to mess with the OS settings.

3

There is of course a command to change the timezone:

sudo timedatectl set-timezone Asia/Shanghai

To use it you need

  • To be able to see the timedatectl command from within docker.
  • Passwordless sudo access for the Node-red user.

If you can do that I've no idea if it would change the timezone outside of the docker container - which as @Colin says is designed to prevent such jiggery-pokery.

1 Like
4

I believe I miscommunicated earlier. :sweat_smile:

What I actually need is to change the timezone inside the Docker container, not the host system's timezone. Also, using sudo isn't an option because Alpine-based Docker images (like the one used by Node-RED) typically don’t include sudo by default.

5

If you open a terminal window inside the docker container, what command would you use to do what you want?

6

I'm using the same commands (ln -s /usr/share/zoneinfo/Asia/Shanghai /etc/localtime) , but I tried to simplify the process by triggering them through the inject node. I suspect the issue is related to permissions—when I run the commands directly from the terminal, they execute with root privileges, which might be why they work there but not through the inject node.

7

The correct way is to pass the TZ environment variable into the container.

e.g

docker run -e TZ=Europe/London -p 1880:1880 nodered/node-red:latest
2 Likes
8

Ok! Thanks

9

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