fail when backend host is not found (#1385)
This commit is contained in:
Gerrit Germis
Brian Coca
parent
8fac01a3cc
commit
a003b8d081
1 changed files with 99 additions and 116 deletions
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@ -60,6 +60,12 @@ options:
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required: true
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default: null
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choices: [ "enabled", "disabled" ]
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fail_on_not_found:
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description:
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- Fail whenever trying to enable/disable a backend host that does not exist
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required: false
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default: false
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version_added: "2.2"
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wait:
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description:
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- Wait until the server reports a status of 'UP' when `state=enabled`, or
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@ -105,6 +111,9 @@ EXAMPLES = '''
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# disable backend server in 'www' backend pool and drop open sessions to it
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- haproxy: state=disabled host={{ inventory_hostname }} backend=www socket=/var/run/haproxy.sock shutdown_sessions=true
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# disable server without backend pool name (apply to all available backend pool) but fail when the backend host is not found
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- haproxy: state=disabled host={{ inventory_hostname }} fail_on_not_found=yes
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# enable server in 'www' backend pool
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- haproxy: state=enabled host={{ inventory_hostname }} backend=www
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@ -123,6 +132,7 @@ author: "Ravi Bhure (@ravibhure)"
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import socket
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import csv
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import time
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from string import Template
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DEFAULT_SOCKET_LOCATION="/var/run/haproxy.sock"
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@ -156,23 +166,17 @@ class HAProxy(object):
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self.weight = self.module.params['weight']
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self.socket = self.module.params['socket']
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self.shutdown_sessions = self.module.params['shutdown_sessions']
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self.fail_on_not_found = self.module.params['fail_on_not_found']
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self.wait = self.module.params['wait']
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self.wait_retries = self.module.params['wait_retries']
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self.wait_interval = self.module.params['wait_interval']
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self.command_results = []
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self.status_servers = []
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self.status_weights = []
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self.previous_weights = []
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self.previous_states = []
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self.current_states = []
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self.current_weights = []
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self.command_results = {}
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def execute(self, cmd, timeout=200, capture_output=True):
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"""
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Executes a HAProxy command by sending a message to a HAProxy's local
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UNIX socket and waiting up to 'timeout' milliseconds for the response.
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"""
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self.client = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
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self.client.connect(self.socket)
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self.client.sendall('%s\n' % cmd)
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@ -183,10 +187,67 @@ class HAProxy(object):
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result += buf
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buf = self.client.recv(RECV_SIZE)
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if capture_output:
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self.command_results = result.strip()
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self.capture_command_output(cmd, result.strip())
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self.client.close()
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return result
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def capture_command_output(self, cmd, output):
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"""
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Capture the output for a command
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"""
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if not 'command' in self.command_results.keys():
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self.command_results['command'] = []
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self.command_results['command'].append(cmd)
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if not 'output' in self.command_results.keys():
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self.command_results['output'] = []
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self.command_results['output'].append(output)
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def discover_all_backends(self):
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"""
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Discover all entries with svname = 'BACKEND' and return a list of their corresponding
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pxnames
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"""
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data = self.execute('show stat', 200, False).lstrip('# ')
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r = csv.DictReader(data.splitlines())
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return map(lambda d: d['pxname'], filter(lambda d: d['svname'] == 'BACKEND', r))
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def execute_for_backends(self, cmd, pxname, svname, wait_for_status = None):
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"""
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Run some command on the specified backends. If no backends are provided they will
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be discovered automatically (all backends)
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"""
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# Discover backends if none are given
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if pxname is None:
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backends = self.discover_all_backends()
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else:
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backends = [pxname]
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# Run the command for each requested backend
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for backend in backends:
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# Fail when backends were not found
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state = self.get_state_for(backend, svname)
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if (self.fail_on_not_found or self.wait) and state is None:
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self.module.fail_json(msg="The specified backend '%s/%s' was not found!" % (backend, svname))
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self.execute(Template(cmd).substitute(pxname = backend, svname = svname))
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if self.wait:
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self.wait_until_status(backend, svname, wait_for_status)
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def get_state_for(self, pxname, svname):
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"""
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Find the state of specific services. When pxname is not set, get all backends for a specific host.
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Returns a list of dictionaries containing the status and weight for those services.
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"""
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data = self.execute('show stat', 200, False).lstrip('# ')
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r = csv.DictReader(data.splitlines())
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state = map(lambda d: { 'status': d['status'], 'weight': d['weight'] }, filter(lambda d: (pxname is None or d['pxname'] == pxname) and d['svname'] == svname, r))
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return state or None
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def wait_until_status(self, pxname, svname, status):
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"""
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Wait for a service to reach the specified status. Try RETRIES times
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@ -195,49 +256,16 @@ class HAProxy(object):
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not found, the module will fail.
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"""
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for i in range(1, self.wait_retries):
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data = self.execute('show stat', 200, False).lstrip('# ')
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r = csv.DictReader(data.splitlines())
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found = False
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for row in r:
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if row['pxname'] == pxname and row['svname'] == svname:
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found = True
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if row['status'] == status:
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return True;
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else:
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time.sleep(self.wait_interval)
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state = self.get_state_for(pxname, svname)
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if not found:
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self.module.fail_json(msg="unable to find server %s/%s" % (pxname, svname))
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# We can assume there will only be 1 element in state because both svname and pxname are always set when we get here
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if state[0]['status'] == status:
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return True
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else:
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time.sleep(self.wait_interval)
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self.module.fail_json(msg="server %s/%s not status '%s' after %d retries. Aborting." % (pxname, svname, status, self.wait_retries))
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def get_current_state(self, host, backend):
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"""
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Gets the each original state value from show stat.
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Runs before and after to determine if values are changed.
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This relies on weight always being the next element after
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status in "show stat" as well as status states remaining
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as indicated in status_states and haproxy documentation.
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"""
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output = self.execute('show stat')
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output = output.lstrip('# ').strip()
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output = output.split(',')
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result = output
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status_states = [ 'UP','DOWN','DRAIN','NOLB','MAINT' ]
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self.status_server = []
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status_weight_pos = []
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self.status_weight = []
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for check, status in enumerate(result):
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if status in status_states:
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self.status_server.append(status)
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status_weight_pos.append(check + 1)
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for weight in status_weight_pos:
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self.status_weight.append(result[weight])
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return{'self.status_server':self.status_server, 'self.status_weight':self.status_weight}
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def enabled(self, host, backend, weight):
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"""
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@ -245,33 +273,11 @@ class HAProxy(object):
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also supports to get current weight for server (default) and
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set the weight for haproxy backend server when provides.
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"""
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svname = host
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if self.backend is None:
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output = self.execute('show stat')
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#sanitize and make a list of lines
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output = output.lstrip('# ').strip()
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output = output.split('\n')
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result = output
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cmd = "get weight $pxname/$svname; enable server $pxname/$svname"
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if weight:
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cmd += "; set weight $pxname/$svname %s" % weight
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self.execute_for_backends(cmd, backend, host, 'UP')
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for line in result:
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if 'BACKEND' in line:
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result = line.split(',')[0]
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pxname = result
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cmd = "get weight %s/%s ; enable server %s/%s" % (pxname, svname, pxname, svname)
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if weight:
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cmd += "; set weight %s/%s %s" % (pxname, svname, weight)
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self.execute(cmd)
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if self.wait:
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self.wait_until_status(pxname, svname, 'UP')
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else:
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pxname = backend
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cmd = "get weight %s/%s ; enable server %s/%s" % (pxname, svname, pxname, svname)
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if weight:
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cmd += "; set weight %s/%s %s" % (pxname, svname, weight)
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self.execute(cmd)
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if self.wait:
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self.wait_until_status(pxname, svname, 'UP')
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def disabled(self, host, backend, shutdown_sessions):
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"""
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@ -279,64 +285,40 @@ class HAProxy(object):
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performed on the server until it leaves maintenance,
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also it shutdown sessions while disabling backend host server.
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"""
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svname = host
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if self.backend is None:
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output = self.execute('show stat')
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#sanitize and make a list of lines
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output = output.lstrip('# ').strip()
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output = output.split('\n')
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result = output
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cmd = "get weight $pxname/$svname; disable server $pxname/$svname"
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if shutdown_sessions:
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cmd += "; shutdown sessions server $pxname/$svname"
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self.execute_for_backends(cmd, backend, host, 'MAINT')
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for line in result:
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if 'BACKEND' in line:
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result = line.split(',')[0]
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pxname = result
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cmd = "get weight %s/%s ; disable server %s/%s" % (pxname, svname, pxname, svname)
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if shutdown_sessions:
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cmd += "; shutdown sessions server %s/%s" % (pxname, svname)
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self.execute(cmd)
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if self.wait:
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self.wait_until_status(pxname, svname, 'MAINT')
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else:
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pxname = backend
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cmd = "get weight %s/%s ; disable server %s/%s" % (pxname, svname, pxname, svname)
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if shutdown_sessions:
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cmd += "; shutdown sessions server %s/%s" % (pxname, svname)
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self.execute(cmd)
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if self.wait:
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self.wait_until_status(pxname, svname, 'MAINT')
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def act(self):
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"""
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Figure out what you want to do from ansible, and then do it.
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"""
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self.get_current_state(self.host, self.backend)
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self.previous_states = ','.join(self.status_server)
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self.previous_weights = ','.join(self.status_weight)
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# Get the state before the run
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state_before = self.get_state_for(self.backend, self.host)
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self.command_results['state_before'] = state_before
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# toggle enable/disbale server
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if self.state == 'enabled':
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self.enabled(self.host, self.backend, self.weight)
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elif self.state == 'disabled':
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self.disabled(self.host, self.backend, self.shutdown_sessions)
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else:
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self.module.fail_json(msg="unknown state specified: '%s'" % self.state)
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self.get_current_state(self.host, self.backend)
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self.current_states = ','.join(self.status_server)
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self.current_weights = ','.join(self.status_weight)
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# Get the state after the run
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state_after = self.get_state_for(self.backend, self.host)
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self.command_results['state_after'] = state_after
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if self.current_weights != self.previous_weights:
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self.module.exit_json(stdout=self.command_results, changed=True)
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elif self.current_states != self.previous_states:
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self.module.exit_json(stdout=self.command_results, changed=True)
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# Report change status
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if state_before != state_after:
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self.command_results['changed'] = True
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self.module.exit_json(**self.command_results)
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else:
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self.module.exit_json(stdout=self.command_results, changed=False)
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self.command_results['changed'] = False
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self.module.exit_json(**self.command_results)
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def main():
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@ -349,11 +331,11 @@ def main():
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weight=dict(required=False, default=None),
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socket = dict(required=False, default=DEFAULT_SOCKET_LOCATION),
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shutdown_sessions=dict(required=False, default=False),
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fail_on_not_found=dict(required=False, default=False, type='bool'),
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wait=dict(required=False, default=False, type='bool'),
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wait_retries=dict(required=False, default=WAIT_RETRIES, type='int'),
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wait_interval=dict(required=False, default=WAIT_INTERVAL, type='int'),
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),
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)
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if not socket:
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@ -366,3 +348,4 @@ def main():
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from ansible.module_utils.basic import *
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main()
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