Node cache migration

A non-transitory computer readable medium having program instructions stored thereon that are executable by a computer system to cause the computer system to perform operations comprising:

• detecting that there is an updated node image that is an updated version to a previous node image used to deploy a set of virtual machines;
• selecting, from the set of virtual machines, a first virtual machine for which to perform a node image upgrade process, wherein the first virtual machine uses a first volume to store data of a set of applications executing on the first virtual machine;
• and
• performing the node image upgrade process for the first virtual machine, wherein the performing includes:
• deploying a second virtual machine based on the updated node image, wherein the first virtual machine was deployed based on the previous node image;
• maintaining a set of mappings that maps the set of applications to the first virtual machine and the first virtual machine to the second virtual machine;
• after the deploying of the second virtual machine, transitioning the first virtual machine to a read-only mode in which read transactions but not write transactions are routed to the set of applications;
• after the transitioning, performing, based on the set of mappings, a copy operation to copy the data of the set of applications from the first volume used by the first virtual machine to a second volume used by the second virtual machine;
• and
• after completion of the copy operation:
• scaling down the first virtual machine;
• and
• after the scaling down of the first virtual machine, redeploying, based on the set of mappings, the set of applications on the second virtual machine.

A system, comprising:

• at least one processor;
• and
• memory having program instructions stored thereon that are executable by the at least one processor to cause the system to perform operations comprising:
• detecting that there is an updated node image that is an updated version to a previous node image used to deploy a set of virtual machines;
• selecting, from the set of virtual machines, a first virtual machine for which to perform a node image upgrade process, wherein the first virtual machine uses a first volume to store data of a set of applications executing on the first virtual machine;
• and
• performing the node image upgrade process for the first virtual machine, wherein the performing includes:
• deploying a second virtual machine based on the updated node image, wherein the first virtual machine was deployed based on the previous node image;
• maintaining a set of mappings that maps the set of applications to the first virtual machine and the first virtual machine to the second virtual machine;
• after the deploying of the second virtual machine, transitioning the first virtual machine to a read-only mode in which read transactions but not write transactions are routed to the set of applications;
• after the transitioning, performing a copy operation to copy the data of the set of applications from the first volume used by the first virtual machine to a second volume used by the second virtual machine;
• and
• after completion of the copy operation:
• scaling down the first virtual machine;
• and
• after the scaling down of the first virtual machine, redeploying, based on the set of mappings, the set of applications on the second virtual machine.