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Diffstat (limited to 'doc/merging.rst')
| -rw-r--r-- | doc/merging.rst | 24 |
1 files changed, 15 insertions, 9 deletions
diff --git a/doc/merging.rst b/doc/merging.rst index 4046338b..2967ca9d 100644 --- a/doc/merging.rst +++ b/doc/merging.rst @@ -1,15 +1,16 @@ Overview -------- -This was done because it has been a common feature request that there be a -way to specify how cloud-config yaml "dictionaries" are merged together when -there are multiple yamls to merge together (say when performing an #include). +This was implemented because it has been a common feature request that there be +a way to specify how cloud-config yaml "dictionaries" provided as user-data are +merged together when there are multiple yamls to merge together (say when +performing an #include). Since previously the merging algorithm was very simple and would only overwrite and not append lists, or strings, and so on it was decided to create a new and improved way to merge dictionaries (and there contained objects) together in a -way that is customizable, thus allowing for users who provide cloud-config data -to determine exactly how there objects will be merged. +way that is customizable, thus allowing for users who provide cloud-config +user-data to determine exactly how there objects will be merged. For example. @@ -181,8 +182,13 @@ cloud-config dictionary coming after it. Other uses ---------- -The default merging algorithm for merging 'conf.d' yaml files (which form a initial -yaml config for cloud-init) was also changed to use this mechanism so its full +In addition to being used for merging user-data sections, the default merging +algorithm for merging 'conf.d' yaml files (which form an initial yaml config +for cloud-init) was also changed to use this mechanism so its full benefits (and customization) can also be used there as well. Other places that -used the previous merging are also similar now extensible (metadata merging for -example). +used the previous merging are also, similarly, now extensible (metadata +merging, for example). + +Note, however, that merge algorithms are not used *across* types of +configuration. As was previously the case, merged user-data will still +overwrite conf.d configuration. |