Change default of [kubernetes] enable_tcp_keepalive to True (apac…

…he#15338)

We've seen instances of connection resets happening, particularly in
Azure, that are remedied by enabling tcp_keepalive. Enabling it by
default should be safe and sane regardless of where we are running.

(cherry picked from commit 6e31465)

airflow/config_templates/config.yml

@@ -2065,7 +2065,7 @@
       version_added: ~
       type: boolean
       example: ~
-      default: "False"
+      default: "True"
     - name: tcp_keep_idle
       description: |
         When the `enable_tcp_keepalive` option is enabled, TCP probes a connection that has

airflow/config_templates/default_airflow.cfg

@@ -1014,7 +1014,7 @@ delete_option_kwargs =
 
 # Enables TCP keepalive mechanism. This prevents Kubernetes API requests to hang indefinitely
 # when idle connection is time-outed on services like cloud load balancers or firewalls.
-enable_tcp_keepalive = False
+enable_tcp_keepalive = True
 
 # When the `enable_tcp_keepalive` option is enabled, TCP probes a connection that has
 # been idle for `tcp_keep_idle` seconds.

airflow/kubernetes/kube_client.py

@@ -80,9 +80,9 @@ def _enable_tcp_keepalive() -> None:
 
     from urllib3.connection import HTTPConnection, HTTPSConnection
 
-    tcp_keep_idle = conf.getint('kubernetes', 'tcp_keep_idle', fallback=120)
-    tcp_keep_intvl = conf.getint('kubernetes', 'tcp_keep_intvl', fallback=30)
-    tcp_keep_cnt = conf.getint('kubernetes', 'tcp_keep_cnt', fallback=6)
+    tcp_keep_idle = conf.getint('kubernetes', 'tcp_keep_idle')
+    tcp_keep_intvl = conf.getint('kubernetes', 'tcp_keep_intvl')
+    tcp_keep_cnt = conf.getint('kubernetes', 'tcp_keep_cnt')
 
     socket_options = [
         (socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1),
@@ -120,7 +120,7 @@ def get_kube_client(
         if config_file is None:
             config_file = conf.get('kubernetes', 'config_file', fallback=None)
 
-    if conf.getboolean('kubernetes', 'enable_tcp_keepalive', fallback=False):
+    if conf.getboolean('kubernetes', 'enable_tcp_keepalive'):
         _enable_tcp_keepalive()
 
     client_conf = _get_kube_config(in_cluster, cluster_context, config_file)