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add documentation for the server & client side timeout
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Priyankasaggu11929 committed May 31, 2021
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Expand Up @@ -17,6 +17,47 @@
The script will wait for 10 events related to namespaces to occur within
the `timeout_seconds` threshold and then move on to wait for another 10 events
related to pods to occur within the `timeout_seconds` threshold.
---
[INFO] Timeout settings
There are two inputs available in the client, that could be used to set connection timeouts:
1. timeout_seconds
2. _request_timeout
a) Sever-side timeout ("kwargs['timeout_seconds'] = n")
- The value of the argument `timeout_seconds`, n (which is time duration in seconds) is consumed at the server side, and is included in the request URL to the server. For eg. ~
"https://localhost:6443/api/v1/namespaces/default/pods?labelSelector=app%3Ddemo&timeoutSeconds=100&watch=True."
- If the `timeout_seconds` value is set, for ex: "kwargs['timeout_seconds'] = 3600", then the server timeout will be equal to 1 hour, as determined by the following expression ~
"timeout = time.Duration(3600) * time.seconds" -> "timeout = 1 hour"
Refer: https://github.com/kubernetes/apiserver/blob/92392ef22153d75b3645b0ae339f89c12767fb52/pkg/endpoints/handlers/get.go#L255
- If the `timeout_seconds` value is not set, then the connection timeout will be a randomized value (in seconds) between 0 and `minRequestTimeout`, to spread out load. It is determined by the following expression ~
"timeout = time.Duration(float64(minRequestTimeout) * (rand.Float64() + 1.0))",
Where `minRequestTimeout` indicates the minimum number of seconds a handler must keep a request open before timing it out. The default value of `minRequestTimeout` is 1800 seconds.
Refer: https://github.com/kubernetes/apiserver/blob/92392ef22153d75b3645b0ae339f89c12767fb52/pkg/endpoints/handlers/get.go#L258
https://github.com/kubernetes/kubernetes/blob/release-1.1/docs/admin/kube-apiserver.md
- In case of a network outage, the timeout value will have no effect & the client will hang indefinitely without raising any exception. It is recommended to set this timeout value to a higher number such as 3600 seconds (1 hour).
b) Client-side timeout ("kwargs['_request_timeout'] = n")
- The value of the argument `_request_timeout`, n (which is time duration in seconds) is set to the socket used for the connection.
- The argument `_request_timeout` can accept 2 types of input values, i.e. either in integer (int) type, or a tuple with a length of 2. In case of the tuple input type, the first value will be ignored.
- In case of network outage, leading to dropping all packets with no RST/FIN, the timeout value (in seconds) determined by the `request_timeout` argument, would be the time duration for how long the client will wait before realizing & dropping the connection.
- When the timeout happens, an exception will be raised, for ex ~
"urllib3.exceptions.ReadTimeoutError: HTTPSConnectionPool(host='localhost', port=6443): Read timed out."
- It is recommended to set this timeout value to a low number (for ex ~ maybe 60 seconds)
"""

from kubernetes import client, config, watch
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