This is an example project to control a real-time clock (RTC) attached to the system, from within service in a multicontainer environment on resin.io
The example is adding an RTC to a Raspberry Pi, e.g. a DS1307 module.
The hardware can be enabled by setting dtoverlay=i2c-rtc,ds1307 in config.txt,
or remotely by setting a RESIN_HOST_CONFIG_dtoverlay device configuration to
i2c-rtc,ds1307. See more in the docs regarding customising config.txt.
The RTC control is done in the container by checking whether the RTC time is ahead of the system time, and if it is, then restore the time there.
In the multicontainer, unprivileged environment this requires:
- access to
/dev/rtc - the system capability to set time
These are set up in docker-compose.yml, as the example shows, and would enable
time control with minimal privileges.
Note: this is an example project, and depending on your requirements and on the base images used in your services, you might need to modify the setup.
This project can be adapted for non-multicontainer resin.io environments,
where basically just rtc/start.sh, and the RTC-to-system-time logic within
that script is required.
Copyright 2018 Resinio Ltd.
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.