Changes between Version 44 and Version 45 of Eucalyptus-1.5.2-Setup

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Timestamp:
04/06/10 15:33:20 (9 years ago)
Author:
ibaldin (IP: 152.54.9.131)
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  • Eucalyptus-1.5.2-Setup

    v44 v45  
    140140# euca_conf -addnode compute-node.name.or.ip 
    141141}}} 
     142 
     143=== How Eucalyptus allocates VLAN tags === 
     144 
     145Eucalyptus uses vlans as an isolation mechanism between security groups. When a security group is created (euca-add-group) and then instances (VMs) are created within the group, Euca allocates a VLAN for this group, creates bridges in individual hosts (head and worker/client nodes) and attaches VMs to those bridges, instead of the default bridge. VLAN allocation in Eucalyptus is simple. In the configuration file there is a VNET_NETMASK parameter that indicates to it the width of the mask for address assignment, and, consequently, the total number of VMs that can be created (let's call this MAXHOSTS = 2^(32-MASK_WIDTH)-2 ). The VNET_ADDRSPERNET parameter dictates the maximum number of VMs per security group/VLAN. Therefore the total number of VLANs that the system will use will be MAXHOSTS/VNET_ADDRSPERNET and the maximum VLAN tag Eucalyptus will use appears to be MAXHOSTS/VNET_ADDRSPERNET -1. For example for a 24 bit mask, MAXHOSTS=254 and for VNET_ADDRSPERNET=16, the maximum VLAN tag Eucalyptus will use will be 15. Default VLAN tag is 10 (for a default security group). 
    142146 
    143147=== Testing Eucalyptus ===