US 2019/0294204 A1 · CLOCK SYNCHRONIZATION

Abstract

In various examples, there is provided methods performed by nodes in a cluster of nodes to establish a master clock at a new master node following a reconfiguration of the nodes included in the cluster, whereby the master clock is provided by an old master node prior to the reconfiguration, and synchronize a local clock of slave nodes to clock of the new master node. The new master node sends a message to the slave nodes instructing them to disable their respective local clocks, receives acknowledgements that the local clocks have been disabled, waits until a time at which all leases have expired for any nodes removed from the cluster, sets the value of its clock to be greater than a maximum value that could have been provided by the old master node at the time the leases expired and indicates to the other nodes to re-enable their local clocks.

Claims20

Dependent claims

A method performed by a new master node in a cluster of nodes to establish a master clock using a local clock on the new master node following a reconfiguration of the nodes included in the cluster, wherein each of the nodes in the cluster comprises a respective local clock which is synchronized to the master clock, the master clock being provided by an old master node prior to the reconfiguration, the method comprising:

sending a message to the other nodes in the cluster of nodes instructing them to disable their respective local clocks;
receiving respective acknowledgements from the other nodes in the cluster of nodes indicating that their respective local clocks have been disabled;
identifying a time at which all leases of any nodes which have been removed from the cluster of nodes by the reconfiguration will have expired;
waiting until the identified time has passed;
determining a maximum value that the master clock provided by the old master node could have been at the identified time;
setting the local clock to be greater than the maximum value;
and
indicating to the other nodes in the cluster of nodes to re-enable their respective local clocks.

5 more elements

A method performed by a slave node in a cluster of nodes to synchronize a local clock of the slave node to a master clock for the cluster of nodes, the master clock being provided by a master node of the cluster of nodes, the method comprising:

synchronizing the local clock to the master node;
receiving an indication of a new configuration for the cluster, the new configuration indicating a new master node for the cluster;
receiving a message from the new master node instructing the slave node to disable the local clock;
disabling the local clock;
sending a message to the new master node indicating that the local clock has been disabled;
receiving an indication from the new master node that the local clock should be re-enabled;
and
synchronizing the local clock based on timestamps received from the new master node.

5 more elements

A system for use in a cluster of nodes, the system comprising:

a local clock;
and
a clock synchronization module arranged to synchronize to a master clock for the cluster of nodes provided by a master node of the cluster of nodes, wherein following receipt of a new configuration for the cluster indicating a new master node, the clock synchronization module is arranged to:
disable the local clock in response to receiving a message from the new master node instructing the slave node to disable the local clock;
send a message to the new master node indicating that the local clock has been disabled;
re-enable the local clock in response to receiving an indication from the new master node that the local clock should be re-enabled;
and
synchronize the local clock based on timestamps received from the new master node.

5 more elements

Dependencies are inferred from the claim text.

Clock synchronization

Life of this patent

Clock synchronization

Life of this patent

Abstract

Claims20