Secure booting of virtualization managers

A system, comprising:

• a virtualization host of a computing service of a provider network, wherein the virtualization host comprises a first offload card, wherein the first offload card includes one or components of a virtualization manager;
• wherein the one or more components are configured to:
• initiate a first phase of a multi-phase boot operation of the virtualization manager, wherein the first phase comprises using a first key pair, wherein a particular key of the first key pair is stored in a tamper-resistant location;
• in response to determining that the first phase has completed successfully, initiate a second phase of the multi-phase boot operation, wherein the second phase comprises (a) measuring one or more firmware programs using a security module and (b) launching a first version of a virtualization coordinator at the first offload card;
• obtain, using the first version of the virtualization coordinator, a different version of the virtualization coordinator;
• launch the different version of the virtualization coordinator at the first offload card;
• and
• initialize one or more other components of the virtualization manager to complete the multi-phase boot operation, including at least one component which runs at a processor which is not installed on the first offload card.

A non-transitory computer-accessible storage medium storing program instructions that when executed on one or more processors:

• initiate, at a first offload card of a virtualization host, a first phase of a multi-phase boot operation of a virtualization manager of the virtualization host, wherein the first phase comprises using a first key pair, wherein a particular key of the first key pair is stored in a tamper-resistant location;
• in response to determining that the first phase has completed successfully, initiate a second phase of the multi-phase boot operation, wherein the second phase comprises (a) measuring one or more firmware programs using a security module and (b) launching a first version of a virtualization coordinator at a first offload card of the virtualization host;
• obtain, using the first version of the virtualization coordinator, a different version of the virtualization coordinator;
• launch the different version of the virtualization coordinator at the first offload card;
• and
• initialize one or more other components of the virtualization manager to complete the multi-phase boot operation, including at least one component which runs at a processor which is not installed on the first offload card.