Introduction

phosphor-time-manager is the time manager service that implements dbus interface xyz/openbmc_project/Time/EpochTime.interface.yaml. 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 dbus:

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

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

User can directly get or set the property Elasped 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 below two settings in settings manager.

• TimeSyncMethod
  • NTP: Time is set via NTP server.
  • MANUAL: 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 owns 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

Special note on host on

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

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