CSIT-845 Capture VPP core-dump from vpp crash on DUTsrls1901

Change-Id: I987dcd5092d8527c9aefbe093e1ed7ae144d191b
Signed-off-by: Peter Mikus <pmikus@cisco.com>

7 files changed, 336 insertions, 86 deletions

diff --git a/resources/libraries/python/CoreDumpUtil.py b/resources/libraries/python/CoreDumpUtil.py
new file mode 100644
index 0000000000..7843a59c09
--- /dev/null
+++ b/resources/libraries/python/CoreDumpUtil.py
@@ -0,0 +1,159 @@
+# Copyright (c) 2019 Cisco and/or its affiliates.
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at:
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Core dump library."""
+
+from time import time
+
+from resources.libraries.python.constants import Constants
+from resources.libraries.python.DUTSetup import DUTSetup
+from resources.libraries.python.LimitUtil import LimitUtil
+from resources.libraries.python.SysctlUtil import SysctlUtil
+from resources.libraries.python.ssh import exec_cmd_no_error, scp_node
+from resources.libraries.python.topology import NodeType
+
+__all__ = ["CoreDumpUtil"]
+
+
+class CoreDumpUtil(object):
+    """Class contains methods for processing core dumps."""
+
+    # Use one instance of class for all tests. If the functionality should
+    # be enabled per suite or per test case, change the scope to "TEST SUITE" or
+    # "TEST CASE" respectively.
+    ROBOT_LIBRARY_SCOPE = 'GLOBAL'
+
+    def __init__(self):
+        """Initialize CoreDumpUtil class."""
+        # Corekeeper is configured.
+        self._corekeeper_configured = False
+        # Enable setting core limit for process. This can be used to prevent
+        # library to further set the core limit for unwanted behavior.
+        self._core_limit_enabled = True
+
+    def set_core_limit_enabled(self):
+        """Enable setting of core limit for PID."""
+        self._core_limit_enabled = True
+
+    def set_core_limit_disabled(self):
+        """Disable setting of core limit for PID."""
+        self._core_limit_enabled = False
+
+    def is_core_limit_enabled(self):
+        """Check if core limit is set for process.
+
+        :returns: True if core limit is set for process.
+        :rtype: bool
+        """
+        return self._corekeeper_configured and self._core_limit_enabled
+
+    def setup_corekeeper_on_all_nodes(self, nodes):
+        """Setup core dumps system wide on all nodes.
+
+        :param nodes: Nodes in the topology.
+        :type nodes: dict
+        """
+        for node in nodes.values():
+            # Any binary which normally would not be dumped is dumped anyway,
+            # but only if the "core_pattern" kernel sysctl is set to either a
+            # pipe handler or a fully qualified path. (For more details on this
+            # limitation, see CVE-2006-2451.) This mode is appropriate when
+            # administrators are attempting to debug problems in a normal
+            # environment, and either have a core dump pipe handler that knows
+            # to treat privileged core dumps with care, or specific directory
+            # defined for catching core dumps. If a core dump happens without a
+            # pipe handler or fully qualifid path, a message will be emitted to
+            # syslog warning about the lack of a correct setting.
+            SysctlUtil.set_sysctl_value(node, 'fs.suid_dumpable', 2)
+
+            # Specify a core dumpfile pattern name (for the output filename).
+            # %p    pid
+            # %u    uid (in initial user namespace)
+            # %g    gid (in initial user namespace)
+            # %s    signal number
+            # %t    UNIX time of dump
+            # %h    hostname
+            # %e    executable filename (may be shortened)
+            SysctlUtil.set_sysctl_value(node, 'kernel.core_pattern',
+                                        Constants.KERNEL_CORE_PATTERN)
+
+        self._corekeeper_configured = True
+
+    @staticmethod
+    def enable_coredump_limit(node, pid):
+        """Enable coredump for PID(s) by setting no core limits.
+
+        :param node: Node in the topology.
+        :param pid: Process ID(s) to set core dump limit to unlimited.
+        :type node: dict
+        :type pid: list or int
+        """
+        if isinstance(pid, list):
+            for item in pid:
+                LimitUtil.set_pid_limit(node, item, 'core', 'unlimited')
+                LimitUtil.get_pid_limit(node, item)
+        else:
+            LimitUtil.set_pid_limit(node, pid, 'core', 'unlimited')
+            LimitUtil.get_pid_limit(node, pid)
+
+    def enable_coredump_limit_vpp_on_all_duts(self, nodes):
+        """Enable coredump for all VPP PIDs by setting no core limits on all
+        DUTs if setting of core limit by this library is enabled.
+
+        :param nodes: Nodes in the topology.
+        :type nodes: dict
+        """
+        for node in nodes.values():
+            if node['type'] == NodeType.DUT and self.is_core_limit_enabled():
+                vpp_pid = DUTSetup.get_vpp_pid(node)
+                self.enable_coredump_limit(node, vpp_pid)
+
+    def get_core_files_on_all_nodes(self, nodes, disable_on_success=True):
+        """Compress all core files into single file and remove the original
+        core files on all nodes.
+
+        :param nodes: Nodes in the topology.
+        :param disable_on_success: If True, disable setting of core limit by
+            this instance of library. Default: True
+        :type nodes: dict
+        :type disable_on_success: bool
+        """
+        for node in nodes.values():
+            uuid = str(time()).replace('.', '')
+            name = '{uuid}.tar.lzo.lrz.xz'.format(uuid=uuid)
+
+            command = ('[ -e {dir}/*.core ] && sudo tar c {dir}/*.core | '
+                       'lzop -1 | '
+                       'lrzip -n -T -p 1 -w 5 | '
+                       'xz -9e > {dir}/{name} && '
+                       'sudo rm -f {dir}/*.core'
+                       .format(dir=Constants.CORE_DUMP_DIR, name=name))
+            try:
+                exec_cmd_no_error(node, command, timeout=3600)
+                if disable_on_success:
+                    self.set_core_limit_disabled()
+            except RuntimeError:
+                # If compress was not sucessfull ignore error and skip further
+                # processing.
+                continue
+
+            local_path = 'archive/{name}'.format(name=name)
+            remote_path = '{dir}/{name}'.format(dir=Constants.CORE_DUMP_DIR,
+                                                name=name)
+            try:
+                scp_node(node, local_path, remote_path, get=True, timeout=3600)
+                command = 'rm -f {dir}/{name}'\
+                           .format(dir=Constants.CORE_DUMP_DIR, name=name)
+                exec_cmd_no_error(node, command, sudo=True)
+            except RuntimeError:
+                pass
diff --git a/resources/libraries/python/LimitUtil.py b/resources/libraries/python/LimitUtil.py
new file mode 100644
index 0000000000..45aeaff5a0
--- /dev/null
+++ b/resources/libraries/python/LimitUtil.py
@@ -0,0 +1,60 @@
+# Copyright (c) 2019 Cisco and/or its affiliates.
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at:
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Linux limit library."""
+
+from resources.libraries.python.ssh import exec_cmd_no_error
+
+__all__ = ["LimitUtil"]
+
+
+class LimitUtil(object):
+    """Class contains methods for getting or setting process resource limits."""
+
+    @staticmethod
+    def get_pid_limit(node, pid):
+        """Get process resource limits.
+
+        :param node: Node in the topology.
+        :param pid: Process ID.
+        :type node: dict
+        :type pid: int
+        """
+        command = 'prlimit --noheadings --pid={pid}'.format(pid=pid)
+
+        message = 'Node {host} failed to run: {command}'.\
+            format(host=node['host'], command=command)
+
+        exec_cmd_no_error(node, command, sudo=True, message=message)
+
+    @staticmethod
+    def set_pid_limit(node, pid, resource, limit):
+        """Set process resource limits.
+
+        :param node: Node in the topology.
+        :param pid: Process ID.
+        :param resource: Resource to set limits.
+        :param limit: Limit value.
+        :type node: dict
+        :type pid: int
+        :type resource: str
+        :type limit: str
+        """
+        command = 'prlimit --{resource}={limit} --pid={pid}'.format(
+            resource=resource, limit=limit, pid=pid)
+
+        message = 'Node {host} failed to run: {command}'.\
+            format(host=node['host'], command=command)
+
+        exec_cmd_no_error(node, command, sudo=True, message=message)
+
diff --git a/resources/libraries/python/SysctlUtil.py b/resources/libraries/python/SysctlUtil.py
new file mode 100644
index 0000000000..0db7e2c5e5
--- /dev/null
+++ b/resources/libraries/python/SysctlUtil.py
@@ -0,0 +1,57 @@
+# Copyright (c) 2019 Cisco and/or its affiliates.
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at:
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Linux sysctl library."""
+
+from resources.libraries.python.ssh import exec_cmd_no_error
+
+__all__ = ["SysctlUtil"]
+
+
+class SysctlUtil(object):
+    """Class contains methods for getting or setting sysctl settings."""
+
+    @staticmethod
+    def get_sysctl_value(node, key):
+        """Get sysctl key.
+
+        :param node: Node in the topology.
+        :param key: Key that will be set.
+        :type node: dict
+        :type key: str
+        """
+        command = 'sysctl {key}'.format(key=key)
+
+        message = 'Node {host} failed to run: {command}'.\
+            format(host=node['host'], command=command)
+
+        exec_cmd_no_error(node, command, sudo=True, message=message)
+
+    @staticmethod
+    def set_sysctl_value(node, key, value):
+        """Set sysctl key to specific value.
+
+        :param node: Node in the topology.
+        :param key: Key that will be set.
+        :param value: Value to set.
+        :type node: dict
+        :type key: str
+        :type value: str
+        """
+        command = 'sysctl -w {key}={value}'.format(key=key, value=value)
+
+        message = 'Node {host} failed to run: {command}'.\
+            format(host=node['host'], command=command)
+
+        exec_cmd_no_error(node, command, sudo=True, message=message)
+
diff --git a/resources/libraries/python/constants.py b/resources/libraries/python/constants.py
index 43fbf1a76d..b4a96694b1 100644
--- a/resources/libraries/python/constants.py
+++ b/resources/libraries/python/constants.py
@@ -1,4 +1,4 @@
-# Copyright (c) 2018 Cisco and/or its affiliates.
+# Copyright (c) 2019 Cisco and/or its affiliates.
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at:
@@ -64,3 +64,9 @@ class Constants(object):
 
     # ODL Client Restconf listener port
     ODL_PORT = 8181
+
+    # Sysctl kernel.core_pattern
+    KERNEL_CORE_PATTERN = '/tmp/%p-%u-%g-%s-%t-%h-%e.core'
+
+    # Core dump directory
+    CORE_DUMP_DIR = '/tmp'
diff --git a/resources/libraries/python/ssh.py b/resources/libraries/python/ssh.py
index a23d163768..60f62561be 100644
--- a/resources/libraries/python/ssh.py
+++ b/resources/libraries/python/ssh.py
@@ -22,7 +22,7 @@ from time import time, sleep
 from paramiko import RSAKey, SSHClient, AutoAddPolicy
 from paramiko.ssh_exception import SSHException, NoValidConnectionsError
 from robot.api import logger
-from scp import SCPClient
+from scp import SCPClient, SCPException
 
 
 __all__ = ["exec_cmd", "exec_cmd_no_error"]
@@ -467,3 +467,33 @@ def exec_cmd_no_error(node, cmd, timeout=600, sudo=False, message=None):
         raise RuntimeError(msg)
 
     return stdout, stderr
+
+def scp_node(node, local_path, remote_path, get=False, timeout=30):
+    """Copy files from local_path to remote_path or vice versa.
+
+    :param node: SUT node.
+    :param local_path: Path to local file that should be uploaded; or
+        path where to save remote file.
+    :param remote_path: Remote path where to place uploaded file; or
+        path to remote file which should be downloaded.
+    :param get: scp operation to perform. Default is put.
+    :param timeout: Timeout value in seconds.
+    :type node: dict
+    :type local_path: str
+    :type remote_path: str
+    :type get: bool
+    :type timeout: int
+    :raises RuntimeError: If SSH connection failed or SCP transfer failed.
+    """
+    ssh = SSH()
+
+    try:
+        ssh.connect(node)
+    except SSHException:
+        raise RuntimeError('Failed to connect to {host}!'
+                           .format(host=node['host']))
+    try:
+        ssh.scp(local_path, remote_path, get, timeout)
+    except SCPException:
+        raise RuntimeError('SCP execution failed on {host}!'
+                           .format(host=node['host']))
diff --git a/resources/libraries/robot/performance/performance_setup.robot b/resources/libraries/robot/performance/performance_setup.robot
index 79e98a1170..bda2ae897b 100644
--- a/resources/libraries/robot/performance/performance_setup.robot
+++ b/resources/libraries/robot/performance/performance_setup.robot
@@ -1,4 +1,4 @@
-# Copyright (c) 2018 Cisco and/or its affiliates.
+# Copyright (c) 2019 Cisco and/or its affiliates.
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at:
@@ -667,9 +667,16 @@
 
 # Tests teardowns
 
+| Tear down performance test
+| | [Documentation] | Common test teardown for performance tests.
+| | ...
+| | Remove All Added Ports On All DUTs From Topology | ${nodes}
+| | Show VAT History On All DUTs | ${nodes}
+| | Get Core Files on All Nodes | ${nodes}
+| | Set Test Variable | ${pkt_trace} | ${True}
+
 | Tear down performance discovery test
-| | [Documentation] | Common test teardown for ndrdisc and pdrdisc performance \
-| | ... | tests.
+| | [Documentation] | Common test teardown for ndrpdr performance tests.
 | | ...
 | | ... | *Arguments:*
 | | ... | - rate - Rate for sending packets. Type: string
@@ -683,10 +690,8 @@
 | | ...
 | | [Arguments] | ${rate} | ${framesize} | ${topology_type}
 | | ...
-| | Remove All Added Ports On All DUTs From Topology | ${nodes}
-| | Show VAT History On All DUTs | ${nodes}
-| | Run Keyword If Test Failed
-| | ... | Set Test Variable | ${pkt_trace} | ${True}
+| | Tear down performance test
+| | Show statistics on all DUTs | ${nodes}
 | | Run Keyword If Test Failed
 | | ... | Traffic should pass with no loss | ${perf_trial_duration} | ${rate}
 | | ... | ${framesize} | ${topology_type} | fail_on_loss=${False}
@@ -695,8 +700,7 @@
 | | [Documentation] | Common test teardown for max-received-rate performance
 | | ... | tests.
 | | ...
-| | Remove All Added Ports On All DUTs From Topology | ${nodes}
-| | Show VAT History On All DUTs | ${nodes}
+| | Tear down performance test
 
 | Tear down performance test with wrk
 | | [Documentation] | Common test teardown for ndrdisc and pdrdisc performance \
@@ -706,9 +710,7 @@
 | | ...
 | | ... | \| Tear down performance test with wrk \|
 | | ...
-| | Remove All Added Ports On All DUTs From Topology | ${nodes}
-| | Show VAT History On All DUTs | ${nodes}
-| | Show statistics on all DUTs | ${nodes}
+| | Tear down performance test
 
 | Tear down performance test with container
 | | [Documentation]
@@ -740,19 +742,15 @@
 | | ... | ${dut1_node}=${None} | ${dut1_vm_refs}=${None}
 | | ... | ${dut2_node}=${None} | ${dut2_vm_refs}=${None}
 | | ...
-| | Remove All Added Ports On All DUTs From Topology | ${nodes}
-| | Show VAT History On All DUTs | ${nodes}
+| | Tear down performance discovery test | ${rate} | ${framesize}
+| | ... | ${topology_type}
 | | Show VPP vhost on all DUTs | ${nodes}
-| | Show statistics on all DUTs | ${nodes}
-| | Run Keyword If Test Failed
-| | ... | Traffic should pass with no loss | ${perf_trial_duration} | ${rate}
-| | ... | ${framesize} | ${topology_type} | fail_on_loss=${False}
 | | Run keyword unless | ${dut1_node}==${None}
 | | ... | Tear down guest VM with dpdk-testpmd | ${dut1} | ${dut1_vm_refs}
 | | Run keyword unless | ${dut2_node}==${None}
 | | ... | Tear down guest VM with dpdk-testpmd | ${dut2} | ${dut2_vm_refs}
 
-| Tear down mrr test with vhost and VM with dpdk-testpmd
+| Tear down performance mrr test with vhost and VM with dpdk-testpmd
 | | [Documentation] | Common test teardown for mrr tests which use
 | | ... | vhost(s) and VM(s) with dpdk-testpmd.
 | | ...
@@ -771,10 +769,8 @@
 | | [Arguments] | ${dut1_node}=${None} | ${dut1_vm_refs}=${None}
 | | ... | ${dut2_node}=${None} | ${dut2_vm_refs}=${None}
 | | ...
-| | Remove All Added Ports On All DUTs From Topology | ${nodes}
-| | Show VAT History On All DUTs | ${nodes}
+| | Tear down performance mrr test
 | | Show VPP vhost on all DUTs | ${nodes}
-| | Show statistics on all DUTs | ${nodes}
 | | Run keyword unless | ${dut1_node}==${None}
 | | ... | Tear down guest VM with dpdk-testpmd | ${dut1} | ${dut1_vm_refs}
 | | Run keyword unless | ${dut2_node}==${None}
@@ -818,72 +814,13 @@
 | | [Arguments] | ${dut1_node}=${None} | ${dut1_vm_refs}=${None}
 | | ... | ${dut2_node}=${None} | ${dut2_vm_refs}=${None}
 | | ...
-| | Tear down mrr test with vhost and VM with dpdk-testpmd
+| | Tear down performance mrr test with vhost and VM with dpdk-testpmd
 | | ... | ${dut1_node} | ${dut1_vm_refs}
 | | ... | ${dut2_node} | ${dut2_vm_refs}
 | | Run Keyword If Test Failed | Vpp Log Plugin Acl Settings | ${dut1}
 | | Run Keyword If Test Failed | Run Keyword And Ignore Error
 | | ... | Vpp Log Plugin Acl Interface Assignment | ${dut1}
 
-| Tear down performance pdrchk test with vhost and VM with dpdk-testpmd
-| | [Documentation] | Common test teardown for performance pdrchk tests which \
-| | ... | use vhost(s) and VM(s) with dpdk-testpmd.
-| | ...
-| | ... | *Arguments:*
-| | ... | - rate - Rate for sending packets. Type: string
-| | ... | - framesize - L2 Frame Size [B]. Type: integer
-| | ... | - topology_type - Topology type. Type: string
-| | ... | - dut1_node - Node where to clean qemu. Type: dictionary
-| | ... | - dut1_vm_refs - VM references on node. Type: dictionary
-| | ... | - dut2_node - Node where to clean qemu. Type: dictionary
-| | ... | - dut2_vm_refs - VM references on node. Type: dictionary
-| | ...
-| | ... | *Example:*
-| | ...
-| | ... | \| Tear down performance pdrchk test with vhost and VM with \
-| | ... | dpdk-testpmd \| 4.0mpps \| 64 \| 3-node-IPv4 \| ${node['DUT1']} \
-| | ... | \| ${dut_vm_refs} \| ${node['DUT2']} \| ${dut_vm_refs} \|
-| | ...
-| | [Arguments] | ${rate} | ${framesize} | ${topology_type}
-| | ... | ${dut1_node}=${None} | ${dut1_vm_refs}=${None}
-| | ... | ${dut2_node}=${None} | ${dut2_vm_refs}=${None}
-| | ...
-| | Remove All Added Ports On All DUTs From Topology | ${nodes}
-| | Show VAT History On All DUTs | ${nodes}
-| | Show VPP vhost on all DUTs | ${nodes}
-| | Show statistics on all DUTs | ${nodes}
-| | Run keyword unless | ${dut1_node}==${None}
-| | ... | Tear down guest VM with dpdk-testpmd | ${dut1} | ${dut1_vm_refs}
-| | Run keyword unless | ${dut2_node}==${None}
-| | ... | Tear down guest VM with dpdk-testpmd | ${dut2} | ${dut2_vm_refs}
-
-| Tear down performance mrr test with vhost and VM with dpdk-testpmd
-| | [Documentation] | Common test teardown for performance mrr tests which \
-| | ... | use vhost(s) and VM(s) with dpdk-testpmd.
-| | ...
-| | ... | *Arguments:*
-| | ... | - dut1_node - Node where to clean qemu. Type: dictionary
-| | ... | - dut1_vm_refs - VM references on node. Type: dictionary
-| | ... | - dut2_node - Node where to clean qemu. Type: dictionary
-| | ... | - dut2_vm_refs - VM references on node. Type: dictionary
-| | ...
-| | ... | *Example:*
-| | ...
-| | ... | \| Tear down performance mrr test with vhost and VM with \
-| | ... | dpdk-testpmd \| ${node['DUT1']} \| ${dut_vm_refs} \| ${node['DUT2']} \
-| | ... | \| ${dut_vm_refs} \|
-| | ...
-| | [Arguments] | ${dut1_node}=${None} | ${dut1_vm_refs}=${None}
-| | ... | ${dut2_node}=${None} | ${dut2_vm_refs}=${None}
-| | ...
-| | Remove All Added Ports On All DUTs From Topology | ${nodes}
-| | Show VAT History On All DUTs | ${nodes}
-| | Show VPP vhost on all DUTs | ${nodes}
-| | Run keyword unless | ${dut1_node}==${None}
-| | ... | Tear down guest VM with dpdk-testpmd | ${dut1} | ${dut1_vm_refs}
-| | Run keyword unless | ${dut2_node}==${None}
-| | ... | Tear down guest VM with dpdk-testpmd | ${dut2} | ${dut2_vm_refs}
-
 | Tear down DPDK 2-node performance topology
 | | [Documentation]
 | | ... | Suite teardown phase with traffic generator teardown.
@@ -1045,8 +982,7 @@
 | | ...
 | | ... | \| Tear down mrr test with SRv6 with encapsulation \|
 | | ...
-| | Remove All Added Ports On All DUTs From Topology | ${nodes}
-| | Show VAT History On All DUTs | ${nodes}
+| | Tear down performance mrr test
 | | Run Keyword If Test Failed | Show SR Policies on all DUTs | ${nodes}
 | | Run Keyword If Test Failed
 | | ... | Show SR Steering Policies on all DUTs | ${nodes}
diff --git a/resources/libraries/robot/shared/default.robot b/resources/libraries/robot/shared/default.robot
index 03843c64c6..45bfc08b17 100644
--- a/resources/libraries/robot/shared/default.robot
+++ b/resources/libraries/robot/shared/default.robot
@@ -19,6 +19,7 @@
 | Library | OperatingSystem
 | Library | String
 | ...
+| Library | resources.libraries.python.CoreDumpUtil
 | Library | resources.libraries.python.CpuUtils
 | Library | resources.libraries.python.DUTSetup
 | Library | resources.libraries.python.L2Util
@@ -429,6 +430,7 @@
 | | ${duts}= | Get Matches | ${nodes} | DUT*
 | | :FOR | ${dut} | IN | @{duts}
 | | | Run keyword | ${dut}.Apply Config | restart_vpp=${restart_vpp}
+| | Enable Coredump Limit VPP on All DUTs | ${nodes}
 | | Update All Interface Data On All Nodes | ${nodes} | skip_tg=${True}
 
 | Save VPP PIDs