Changes

Jump to: navigation, search

WP/What are containers

1,069 bytes added, 18:04, 23 March 2011
Memory: added
=== Memory ===
All the containers share the same physical memory and swap space, and other similar resources like a page cache. All that memory is managed by a single kernel, thus making memory distribution model very elastic — if memory is not used by one container, it can be used by another.
{{FIXME|: shared Two major memory resource control parameters that are controlled per container are RAM and swap. If container is off its limit in terms of RAM, kernel tries to free some, by either shrinking the page cacheor by swapping out. This reclamation mechanism is the same as used by a non-containerized kernel, elastic RAM, the only difference is swap out is "virtual swap", RSS reclamationin a sense that kernel does not write physical pages to the disk, kernel vs user memorybut just removes those from container context (?in order to avoid unnecessary I/O), virtual vs physical memorywhile slowing down a container (?to emulate the effect of real swap out). Next, networking buffersif a situation of global (?not per-container)memory shortage happens, moarsuch pages are really swapped out into a swap file on disk. The above memory control mechanism is efficient, moar.easy to use and comprehend by an administrator, and overall very effectiveIn addition, there is an ability to fine-grain control some of the memory-related resources, such as size of IPC shared memory mappings, network buffers, number of processes etc, overall about 20 parameters called User Beancounters.}}
=== Miscellaneous resources ===

Navigation menu