Parallels Virtuozzo Containers 4.6 for Linux

Troubleshooting 355

Problems With Container Operation

Timeout When Accessing Remote Hosts

A host is unreachable by the Hardware Node or its Containers, though it can be reached from other computers.

Solution

Often these timeouts occur due to the fact that the Explicit Congestion Notification (ECN) mechanism of the TCP/IP protocol is on by default in Parallels Virtuozzo Containers and off in some other systems, which leads to their incompatibility. ECN is used to avoid unnecessary packet drops and for some other enhancements. If Parallels Virtuozzo Containers cannot connect to a host, turn off this mechanism:

# sysctl –w net.ipv4.tcp_ecn=0

net.ipv4.tcp_ecn = 0

Extraneous Backups Visible to Container in Parallels Power Panel

Sometimes the

Back Up/Restore Container page in Parallels Power Panel shows backups not belonging to the given Container.

Solution

This happens when two or more Hardware Nodes have Containers with identical IDs hosted on them. If such Containers are backed up onto one and the same Backup Node, they will be able to see the backups of each other by means of Parallels Power Panel. To avoid this situation, you are recommended to have unique Container IDs throughout all your Hardware Nodes.