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https://issues.apache.org/jira/browse/AMBARI-4782?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13915734#comment-13915734
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Dmitry Lysnichenko commented on AMBARI-4782:
--------------------------------------------
[~mahadev] / [~sumitmohanty] / [~u39kun]
I think it would be good to change the desired solution. Currently we have an
inconsistency in our API: "state" parameter has a different meaning in request
and in responce. Talked to UI folks regarding that, they agree that it is an
issue, but are not sure how much the proposed fix will affect the UI.
h2. What is wrong:
HostComponentResourceProvider has two properties defined: "state" and
"desired_state". When we issue a read request like
http://vm-3.vm:8080/api/v1/clusters/cc/host_components?HostRoles/state=INSTALL_FAILED
, the "state" parameter is mapped to "desired_state".
At the same time, "state" property meaning at responce json is a live service
state (so-called current state).
{code}
{
href:
"http://vm-3.vm:8080/api/v1/clusters/cc/hosts/vm-3.vm/host_components/HDFS_CLIENT";,
HostRoles: {
cluster_name: "cc",
component_name: "HDFS_CLIENT",
host_name: "vm-3.vm",
state: "INSTALLED"
},
host: {
href: "http://vm-3.vm:8080/api/v1/clusters/cc/hosts/vm-3.vm";
}
},
{code}
This inconsistency is not obvious and may lead to various issues like
state=INSTALL_FAILED issue mentioned above. So I believe that the right thing
would be to remap "state" parameter to service live state both in requests and
responses (and adjust appropriately web-UI and any third-party tools if
needed). I assume that most party tools will not even notice a difference
because they use "state" parameter as "live state". "current_state" property
should not be added as it will only introduce more confusion.
> Error in getting host components with state INSTALL_FAILED
> ----------------------------------------------------------
>
> Key: AMBARI-4782
> URL: https://issues.apache.org/jira/browse/AMBARI-4782
> Project: Ambari
> Issue Type: Task
> Components: controller, test
> Affects Versions: 1.3.0
> Reporter: Dmitry Lysnichenko
> Assignee: Dmitry Lysnichenko
> Fix For: 1.5.0
>
>
> h2. The problem
> When try to get query on
> api/v1/clusters/<clustername>/host_components?HostRoles/state=INSTALL_FAILED
> Response is
> { "status" : 400, "message" : "Invalid Request: Invalid arguments, invalid
> desired state, desiredState=INSTALL_FAILED" }
> This issue is rooted at the over all issue Ambari has where when "state" is
> specified in the API requests it is always interpreted as "desired_state".
> And INSTALL_FAILED is an invalid "desired_state". Just fixing the GET calls
> to interpret request:state as "state" (current state of a host component)
> might be the right thing to do but will make the get calls to behave
> differently than other calls. For example, request to set all component which
> are in INSTALL_FAILED state to INIT (or MAINTENANCE) will not work as
> expected.
> h2. The proposal:
> The fix is to distinguish between "current_state" and "desired_state" and
> promote "current_state" as a first class query parameter. "state" query
> parameter will be still mapped to "desired_state" to maintain backward
> compatibility.
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