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:

Mode	Owner	Set BMC Time	Set Host Time
NTP	BMC	Fail to set	Not allowed
NTP	HOST	Not allowed	Not allowed
NTP	SPLIT	Fail to set	OK
NTP	BOTH	Fail to set	Not allowed
MANUAL	BMC	OK	Not allowed
MANUAL	HOST	Not allowed	OK
MANUAL	SPLIT	OK	OK
MANUAL	BOTH	OK	OK

• 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.