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 or HOST's time via this interface.

General usage

The service xyz.openbmc_project.Time.Manager provides two objects on D-Bus:

  • /xyz/openbmc_project/time/bmc
  • /xyz/openbmc_project/time/host

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 HOST's time:
    ### With busctl on BMC
    busctl set-property xyz.openbmc_project.Time.Manager \
        /xyz/openbmc_project/time/host 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/host/attr/Elapsed
    

Time settings

Getting BMC or HOST 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.
  • TimeOwner
    • BMC: BMC owns the time and can set the time.
    • HOST: Host owns the time and can set the time.
    • SPLIT: BMC and Host own separate time.
    • BOTH: Both BMC and Host can set the time.

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

ModeOwnerSet BMC TimeSet Host Time
NTPBMCFail to setNot allowed
NTPHOSTNot allowedNot allowed
NTPSPLITFail to setOK
NTPBOTHFail to setNot allowed
MANUALBMCOKNot allowed
MANUALHOSTNot allowedOK
MANUALSPLITOKOK
MANUALBOTHOKOK
  • 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
    
  • To change owner

    ### With busctl on BMC
    busctl set-property xyz.openbmc_project.Settings \
        /xyz/openbmc_project/time/owner xyz.openbmc_project.Time.Owner \
        TimeOwner s xyz.openbmc_project.Time.Owner.Owners.BMC
    
    ### 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.Owner.Owners.BMC" }' \
        https://${BMC_IP}/xyz/openbmc_project/time/owner/attr/TimeOwner
    

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.

Special note on host on

When the host is on, the changes of the above time mode/owner are not applied but deferred. The changes of the mode/owner are saved to persistent storage.

When the host is off, the saved mode/owner are read from persistent storage and are applied.

Note: A user can set the time mode and owner in the settings daemon at any time, but the time manager applying them is governed by the above condition.