Lab are both owners and users the same person is

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Lab are both owners and users, the same person is typically the admin in practice, and so there has been no reason to distinguish between these two cases. Note that all PlanetLab documentation apart from this report refers to the admin role as the principal investigator (PI), but we elect to use the former as it is a more generic term for the corresponding principal. The node state indicates whether the node should (re)install the next time it boots, boot the standard version of the system, or come up in a safe ( debug ) mode that lets PLC inspect the node without allowing any slices to be instantiated or any network traffic to be generated. The MA inspects this field to determine what action to take when a node contacts it. Nodes are initially marked (in the MA database) as being in the install state. 4.8.1 Public Interface The management authority supports two interfaces. The first—which is the public interface to the MA—is used by node owners to register their nodes with PLC. An organization (node owner) enters into a management agreement with PlanetLab through an offline process, during which time PlanetLab learns and verifies the identities of the principals associated with the organization: its administrative and technical contacts. These principals are then allowed to use this interface to upload their public keys into the MA database, and create database entries for their nodes. These operations include: node id = AddNode(auth, node values) UpdateNode(auth, node id, node values) DeleteNode(auth, node id) where node id is an MA-specific unique identifier for the node and node values is a structure that includes the node’s name and IP address. 20
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This public interface also supports operations that allows users (and slice au- thorities) to learn about the set of nodes it manages, so that they know the set of nodes available to deploy slices on: node ids[ ] = GetManagedNode(auth) node values[ ] = GetNodes(auth, node id) Evolution Note: Today, this call returns the DNS name and IP address of a set of nodes managed by PLC. At some point, it makes sense that this file publish a broader set of attributes for available nodes. These attributes would most naturally be represented as an RSpec . 4.8.2 Boot Manager Interface Nodes use the MA’s second interface to contact PLC when they boot. Specifically, the bootfile available on each node (see Section 4.1) contains a minimal Linux system that initializes the node’s hardware, reads the node’s network configuration information from plnode.txt , and contacts PLC. The MA returns an executable program, called the boot manager (approximately 20KB of code), which the node immediately invokes. The boot manager (running on the node) reads the nodekey from plnode.txt , and uses HMAC [5] to authenticate itself to the MA with this key. Each call to the MA is independently authenticated via HMAC. The MA also makes sure the source address corresponds to the one registered for the node, to ensure that the right plnode.txt has been put in the right machine, but this is only a sanity check, as the server trusts that the node is physically secure.
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