Introduction

phosphor-time-manager is the time manager service that implements D-Bus interface xyz/openbmc_project/Time/EpochTime.interface.yaml. The user can get or set the BMC's time via this interface.

General usage

The service xyz.openbmc_project.Time.Manager provides an object on D-Bus:

  • /xyz/openbmc_project/time/bmc

where each object implements interface xyz.openbmc_project.Time.EpochTime.

The user can directly get or set the property Elapsed of the objects to get or set the time. For example on an authenticated session:

  • To get BMC's time:
    ### With busctl on BMC
    busctl get-property xyz.openbmc_project.Time.Manager \
        /xyz/openbmc_project/time/bmc xyz.openbmc_project.Time.EpochTime Elapsed
    
    ### With REST API on remote host
    curl -b cjar -k https://${BMC_IP}/xyz/openbmc_project/time/bmc
    
  • To set BMC's time:
    ### With busctl on BMC
    busctl set-property xyz.openbmc_project.Time.Manager \
        /xyz/openbmc_project/time/bmc xyz.openbmc_project.Time.EpochTime \
        Elapsed t <value-in-microseconds>
    
    ### With REST API on remote host
    curl -b cjar -k -H "Content-Type: application/json" -X PUT \
        -d '{"data": 1487304700000000}' \
        https://${BMC_IP}/xyz/openbmc_project/time/bmc/attr/Elapsed
    

Time settings

Getting BMC time is always allowed, but setting the time may not be allowed depending on the below two settings in the settings manager.

  • TimeSyncMethod
    • NTP: The time is set via NTP server.
    • MANUAL: The time is set manually.

A summary of which cases the time can be set on BMC or HOST:

ModeSet BMC Time
NTPFail to set
MANUALOK
  • To set an NTP server:

    ### With busctl on BMC
    busctl set-property  xyz.openbmc_project.Network \
       /xyz/openbmc_project/network/eth0 \
       xyz.openbmc_project.Network.EthernetInterface NTPServers \
       as 1 "<ntp_server>"
    
    ### With REST API on remote host
    curl -c cjar -b cjar -k -H "Content-Type: application/json" -X  PUT  -d \
        '{"data": ["<ntp_server>"] }' \
        https://${BMC_IP}/xyz/openbmc_project/network/eth0/attr/NTPServers
    
  • To go into NTP mode

    ### With busctl on BMC
    busctl set-property xyz.openbmc_project.Settings \
        /xyz/openbmc_project/time/sync_method xyz.openbmc_project.Time.Synchronization \
        TimeSyncMethod s "xyz.openbmc_project.Time.Synchronization.Method.NTP"
    
    ### With REST API on remote host
    curl -c cjar -b cjar -k -H "Content-Type: application/json" -X  PUT  -d \
        '{"data": "xyz.openbmc_project.Time.Synchronization.Method.NTP" }' \
        https://${BMC_IP}/xyz/openbmc_project/time/sync_method/attr/TimeSyncMethod
    

Special note on changing NTP setting

Starting from OpenBMC 2.6 (with systemd v239), systemd's timedated introduces a new beahvior that it checks the NTP services' status during setting time, instead of checking the NTP setting:

  • When NTP server is set to disabled, and the NTP service is stopping but not stopped, setting time will get an error.

In OpenBMC 2.4 (with systemd v236), the above will always succeed.

This results in openbmc/openbmc#3459, and the related test cases are updated to cooperate with this behavior change.