Abstract: Recovery of virtual machines when one or more hosts fail includes identifying virtual machines running on the remaining functioning hosts. Some of the identified powered on virtual machines are suspended in favor of restarting some of the failed virtual machines from the failed host(s). A subsequent round of identifying virtual machines for suspension and virtual machines for restarting is performed. Virtual machines for suspension and restarting may be identified based on their associated “recovery time objective” (RTO) values or their “maximum number of RTO violations” value.

Abstract: In one embodiment, a method determines a first set of virtual machines and a second set of virtual machines. The first set of virtual machines is associated with a first priority level and the second set of virtual machines is associated with a second priority level. A first set of computing resources and a second set of computing resources are associated with hosts. Upon determining a failure of a host, the method performs: generating a power off request for one or more of the second set of virtual machines powered on the second set of computing resources and generating a power on request for one or more virtual machines from the first set of virtual machines that were powered on the failed host, the power on request powering on the one or more virtual machines from the first set of virtual machines on the second set of computing resources.

Abstract: A system for proactive resource reservation for protecting virtual machines. The system includes a cluster of hosts, wherein the cluster of hosts includes a master host, a first slave host, and one or more other slave hosts, and wherein the first slave host executes one or more virtual machines thereon. The first slave host is configured to identify a failure that impacts an ability of the one or more virtual machines to provide service, and calculate a list of impacted virtual machines. The master host is configured to receive a request to reserve resources on another host in the cluster of hosts to enable the impacted one or more virtual machines to failover, calculate a resource capacity among the cluster of hosts, determine whether the calculated resource capacity is sufficient to reserve the resources, and send an indication as to whether the resources are reserved.

Abstract: A system for monitoring virtual machines includes a master host and a slave host. The slave host includes a primary virtual machine and a secondary virtual machine. The slave host is configured to identify a failure that impacts an ability of at least one of the primary virtual machine and the secondary virtual machine to provide service. If the failure is a Permanent Device Loss failure, the slave host is configured to terminate each impacted virtual machine. If the failure is an All Paths Down failure, the master host is configured to apply one of the following: a first remedy if the primary virtual machine is impacted and the secondary virtual machine is not impacted; a second remedy if the secondary virtual machine is impacted and the primary virtual machine is not impacted; or a third remedy if both the primary virtual machine and the secondary virtual machine are impacted.

Abstract: A system for monitoring a virtual machine executed on a host. The system includes a processor that receives an indication that a failure caused a storage device to be inaccessible to the virtual machine, the inaccessible storage device impacting an ability of the virtual machine to provide service, and applies a remedy to restore access to the storage device based on a type of the failure.

Abstract: In one embodiment, a method attempts, by a computing device, to determine a placement of a set of virtual machines on available hosts upon failure of a host. The placement considers the set of virtual machines as being not powered on any of the available hosts. The method further determines, by the computing device, a placed list of virtual machines in the set of virtual machines as a recommendation to power on to the available hosts. The determination of the placed list of virtual machines is used to determine a power off list of virtual machines in the set of virtual machines to power off, wherein virtual machines in the power off list of virtual machines are currently powered on available hosts but were considered to be powered off to determine the placement.

Abstract: Methods and systems for cluster resource management in virtualized computing environments are described. VM spares are used to reserve (or help discover or otherwise obtain) a set of computing resources for a VM. While VM spares may be used for a variety of scenarios, particular uses of VM spares include using spares to ensure resource availability for requests to power on VMs as well as for discovering, obtaining, and defragmenting the resources and VMs on a cluster, e.g., in response to requests to reserve resources for a VM or to respond to a notification of a failure for a given VM.

Abstract: In one or more embodiments of the invention, communication among host agents providing high availability in a computer cluster is implemented by reading and writing to files on a shared data store. Each host agent holds a lock on a file on the shared data store corresponding to a liveness indicator for the host agent and a coordinator host agent periodically monitors the liveness indicators for host failures.

Abstract: Methods and systems for cluster resource management in virtualized computing environments are described. VM spares are used to reserve (or help discover or otherwise obtain) a set of computing resources for a VM. While VM spares may be used for a variety of scenarios, particular uses of VM spares include using spares to ensure resource availability for requests to power on VMs as well as for discovering, obtaining, and defragmenting the resources and VMs on a cluster, e.g., in response to requests to reserve resources for a VM or to respond to a notification of a failure for a given VM.

Abstract: A method for restarting a virtual machine in a virtual computing system having a plurality of hosts and a resource scheduler for the plurality of hosts includes writing a placement request for the virtual machine to a shared channel that is accessible by the resource scheduler. The method further includes reading a placement result from the shared channel, wherein the placement result is generated by the resource scheduler responsive to the placement request; and restarting the virtual machine in accordance with the placement result.

Abstract: In one embodiment, a method attempts, by a computing device, to determine a placement of a set of virtual machines on available hosts upon failure of a host. The placement considers the set of virtual machines as being not powered on any of the available hosts. The method further determines, by the computing device, a placed list of virtual machines in the set of virtual machines as a recommendation to power on to the available hosts. The determination of the placed list of virtual machines is used to determine a power off list of virtual machines in the set of virtual machines to power off, wherein virtual machines in the power off list of virtual machines are currently powered on available hosts but were considered to be powered off to determine the placement.

Abstract: Embodiments maintain high availability of software application instances in a fault domain. Subordinate hosts are monitored by a master host. The subordinate hosts publish heartbeats via a network and datastores. Based at least in part on the published heartbeats, the master host determines the status of each subordinate host, distinguishing between subordinate hosts that are entirely inoperative and subordinate hosts that are operative but partitioned (e.g., unreachable via the network). The master host may restart software application instances, such as virtual machines, that are executed by inoperative subordinate hosts or that cease executing on partitioned subordinate hosts.

Abstract: Methods and systems for cluster resource management in virtualized computing environments are described. VM spares are used to reserve (or help discover or otherwise obtain) a set of computing resources for a VM. While VM spares may be used for a variety of scenarios, particular uses of VM spares include using spares to ensure resource availability for requests to power on VMs as well as for discovering, obtaining, and defragmenting the resources and VMs on a cluster, e.g., in response to requests to reserve resources for a VM or to respond to a notification of a failure for a given VM.

Abstract: In one or more embodiments of the invention, communication among host agents providing high availability in a computer cluster is implemented by reading and writing to files on a shared data store. Each host agent holds a lock on a file on the shared data store corresponding to a liveness indicator for the host agent and a coordinator host agent periodically monitors the liveness indicators for host failures.

Abstract: A method and apparatus are disclosed for analyzing the operation of one or more network gateways, such as firewalls or routers, that perform a packet filtering function in a network environment. Given a user query, the disclosed firewall analysis tool simulates the behavior of the various firewalls, taking into account the topology of the network environment, and determines which portions of the services or machines specified in the original query would manage to reach from the source to the destination. The relevant packet-filtering configuration files are collected and an internal representation of the implied security policy is derived. A graph data structure is used to represent the network topology. A gateway-zone graph permits the firewall analysis tool to determine where given packets will travel in the network, and which gateways will be encountered along those paths.