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test: add helper functions for debugging
Some utility functions to help when interactively debugging tests, including one to run gdb on the microvm. Signed-off-by: Pablo Barbáchano <[email protected]>
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| # Copyright 2023 Amazon.com, Inc. or its affiliates. All Rights Reserved. | ||
| # SPDX-License-Identifier: Apache-2.0 | ||
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| """Microvm helper functions for interactive use""" | ||
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| import os | ||
| import platform | ||
| import subprocess | ||
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| class DockerInfo: | ||
| """Class to extract information from the Docker environment""" | ||
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| @property | ||
| def ip(self): | ||
| """Return this container's IP address""" | ||
| return ( | ||
| subprocess.check_output( | ||
| "ip -j address show eth0 |jq -r '.[].addr_info[].local'", | ||
| shell=True, | ||
| ) | ||
| .decode("ascii") | ||
| .strip() | ||
| ) | ||
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| @property | ||
| def id(self): | ||
| """Return this container's id""" | ||
| return platform.node() | ||
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| DOCKER = DockerInfo() | ||
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| class MicrovmHelpers: | ||
| """Microvm helper functions for interactive use""" | ||
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| def __init__(self, vm): | ||
| self.vm = vm | ||
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| def print_log(self): | ||
| """Print Firecracker's log""" | ||
| print(self.vm.log_data) | ||
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| def resize_disk(self, disk, size: int = 2**30): | ||
| """Resize a filesystem | ||
| The filesystem should be unmounted for this to work | ||
| """ | ||
| os.truncate(disk, size) | ||
| subprocess.check_output(["resize2fs", disk]) | ||
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| def gdbserver(self, port=2000): | ||
| """Attach gdbserver to the FC process | ||
| See https://sourceware.org/gdb/current/onlinedocs/gdb.html/Remote-Debugging.html#Remote-Debugging | ||
| """ | ||
| comm = f"localhost:{port}" | ||
| subprocess.Popen(["gdbserver", "--attach", comm, str(self.vm.jailer_clone_pid)]) | ||
| print(f"Connect gdb with:\n\tgdb --ex 'target remote {DOCKER.ip}:{port}'") | ||
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| def lldbserver(self, port=2001): | ||
| """Attach lldb-server to the FC process | ||
| See https://lldb.llvm.org/use/remote.html | ||
| TBD does not work. Fails with | ||
| error: attach failed: lost connection | ||
| """ | ||
| # Unlike gdbserver, lldb-server is not a separate package, but is part | ||
| # of lldb and it's about ~400MB to install, so we don't include it in | ||
| # the devctr | ||
| subprocess.run("apt update && apt install lldb", shell=True, check=True) | ||
| subprocess.Popen(["lldb-server", "p", "--listen", f"*:{port}", "--server"]) | ||
| print( | ||
| f"Connect lldb with\n\tlldb -o 'platform select remote-linux' -o 'platform connect connect://{DOCKER.ip}:{port}' -o 'attach {self.vm.jailer_clone_pid}'" | ||
| ) | ||
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| def tmux_neww(self, cmd: str): | ||
| """Open a window in the local tmux""" | ||
| return subprocess.run(["tmux", "neww", cmd], check=True) | ||
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| def how_to_ssh(self): | ||
| """Print how to SSH to the microvm | ||
| This may be useful for example to get a terminal | ||
| """ | ||
| ip = self.vm.iface["eth0"]["iface"].guest_ip | ||
| return f"ip netns exec {self.vm.jailer.netns} ssh -o StrictHostKeyChecking=no -i {self.vm.ssh_key} root@{ip}" | ||
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| def tmux_ssh(self): | ||
| """Open a tmux window with an SSH session to the VM""" | ||
| return self.tmux_neww(self.how_to_ssh()) | ||
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| def enable_console(self): | ||
| """Helper method to attach a console, before the machine boots""" | ||
| if self.vm.api is not None: | ||
| raise RuntimeError(".spawn already called, too late to enable the console") | ||
| if self.vm.boot_args is None: | ||
| self.vm.boot_args = "" | ||
| self.vm.boot_args += "console=ttyS0 reboot=k panic=1" | ||
| self.vm.jailer.daemonize = False | ||
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| def how_to_console(self): | ||
| """Print how to connect to the VM console""" | ||
| return f"screen -dR {self.vm.screen_session}" | ||
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| def tmux_console(self): | ||
| """Open a tmux window with the console""" | ||
| return self.tmux_neww(self.how_to_console()) | ||
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| def how_to_docker(self): | ||
| """How to get into this container from outside""" | ||
| return f"docker exec -it {DOCKER.id}" | ||
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| def enable_ip_forwarding(self): | ||
| """ | ||
| Enables IP forwarding | ||
| TBD this only works for a single microvm. allow several microvms. | ||
| we need to make the veth network smaller and **allocate** them | ||
| accordingly | ||
| """ | ||
| netns = self.vm.jailer.netns | ||
| vethhost = "vethhost0" | ||
| vethhost_ip = "10.0.0.1" | ||
| veth_net = "10.0.0.0/255.255.255.0" | ||
| tap_net = "192.168.0.0/255.255.255.0" | ||
| tap_host_ip = self.vm.iface["eth0"]["iface"].host_ip | ||
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| def run(cmd): | ||
| return subprocess.run(cmd, shell=True, check=True) | ||
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| def run_in_netns(cmd): | ||
| return run(f"ip netns exec {netns} " + cmd) | ||
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| # outside netns | ||
| # iptables -L -v -n | ||
| run(f"ip link add name {vethhost} type veth peer name vethvpn0 netns {netns}") | ||
| run(f"ip addr add {vethhost_ip}/24 dev {vethhost}") | ||
| run_in_netns("ip addr add 10.0.0.2/24 dev vethvpn0") | ||
| run(f"ip link set {vethhost} up") | ||
| run_in_netns("ip link set vethvpn0 up") | ||
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| run("iptables -P FORWARD DROP") | ||
| # iptables -L FORWARD | ||
| # iptables -t nat -L | ||
| run(f"iptables -t nat -A POSTROUTING -s {veth_net} -o eth0 -j MASQUERADE") | ||
| run("iptables -A FORWARD -i eth0 -o vethhost0 -j ACCEPT") | ||
| run("iptables -A FORWARD -i vethhost0 -o eth0 -j ACCEPT") | ||
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| # in the netns | ||
| run_in_netns(f"ip route add default via {vethhost_ip}") | ||
| # tap_ip = ipaddress.ip_network("192.168.0.1/30", False) | ||
| run_in_netns("iptables -A FORWARD -i tap0 -o vethvpn0 -j ACCEPT") | ||
| run_in_netns("iptables -A FORWARD -i vethvpn0 -o tap0 -j ACCEPT") | ||
| run_in_netns( | ||
| f"iptables -t nat -A POSTROUTING -s {tap_net} -o vethvpn0 -j MASQUERADE" | ||
| ) | ||
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| self.vm.ssh.run(f"ip route add default via {tap_host_ip}") | ||
| self.vm.ssh.run("echo nameserver 8.8.8.8 >/etc/resolv.conf") |
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