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From: Ilya Leoshkevich <iii@linux.ibm.com>
To: "Paolo Bonzini" <pbonzini@redhat.com>,
	"Alex Bennée" <alex.bennee@linaro.org>,
	"Ed Maste" <emaste@freebsd.org>, "Li-Wen Hsu" <lwhsu@freebsd.org>,
	"Warner Losh" <imp@bsdimp.com>
Cc: "Marc-André Lureau" <marcandre.lureau@redhat.com>,
	"Daniel P. Berrangé" <berrange@redhat.com>,
	"Thomas Huth" <thuth@redhat.com>,
	"Philippe Mathieu-Daudé" <philmd@linaro.org>,
	"Wainer dos Santos Moschetta" <wainersm@redhat.com>,
	"Beraldo Leal" <bleal@redhat.com>,
	"Kyle Evans" <kevans@freebsd.org>,
	qemu-devel@nongnu.org, "Ilya Leoshkevich" <iii@linux.ibm.com>
Subject: [PATCH 1/3] tests/vm: Set UseDNS=no in the sshd configuration
Date: Thu, 25 Jan 2024 20:48:16 +0100	[thread overview]
Message-ID: <20240125194840.1564-2-iii@linux.ibm.com> (raw)
In-Reply-To: <20240125194840.1564-1-iii@linux.ibm.com>

make vm-build-freebsd sometimes fails with "Connection timed out during
banner exchange". The client strace shows:

    13:59:30 write(3, "SSH-2.0-OpenSSH_9.3\r\n", 21) = 21
    13:59:30 getpid()                       = 252655
    13:59:30 poll([{fd=3, events=POLLIN}], 1, 5000) = 1 ([{fd=3, revents=POLLIN}])
    13:59:32 read(3, "S", 1)                = 1
    13:59:32 poll([{fd=3, events=POLLIN}], 1, 3625) = 1 ([{fd=3, revents=POLLIN}])
    13:59:32 read(3, "S", 1)                = 1
    13:59:32 poll([{fd=3, events=POLLIN}], 1, 3625) = 1 ([{fd=3, revents=POLLIN}])
    13:59:32 read(3, "H", 1)                = 1

There is a 2s delay during connection, and ConnectTimeout is set to 1.
Raising it makes the issue go away, but we can do better. The server
truss shows:

    888: 27.811414714 socket(PF_INET,SOCK_DGRAM|SOCK_CLOEXEC,0) = 5 (0x5)
    888: 27.811765030 connect(5,{ AF_INET 10.0.2.3:53 },16) = 0 (0x0)
    888: 27.812166941 sendto(5,"\^Z/\^A\0\0\^A\0\0\0\0\0\0\^A2"...,39,0,NULL,0) = 39 (0x27)
    888: 29.363970743 poll({ 5/POLLRDNORM },1,5000) = 1 (0x1)

So the delay is due to a DNS query. Disable DNS queries in the server
config.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 tests/vm/basevm.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tests/vm/basevm.py b/tests/vm/basevm.py
index 61725b83254..c0d62c08031 100644
--- a/tests/vm/basevm.py
+++ b/tests/vm/basevm.py
@@ -423,6 +423,8 @@ def console_ssh_init(self, prompt, user, pw):
     def console_sshd_config(self, prompt):
         self.console_wait(prompt)
         self.console_send("echo 'PermitRootLogin yes' >> /etc/ssh/sshd_config\n")
+        self.console_wait(prompt)
+        self.console_send("echo 'UseDNS no' >> /etc/ssh/sshd_config\n")
         for var in self.envvars:
             self.console_wait(prompt)
             self.console_send("echo 'AcceptEnv %s' >> /etc/ssh/sshd_config\n" % var)
-- 
2.43.0



  reply	other threads:[~2024-01-25 19:49 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-01-25 19:48 [PATCH 0/3] make vm-build-freebsd fixes Ilya Leoshkevich
2024-01-25 19:48 ` Ilya Leoshkevich [this message]
2024-01-31 12:51   ` [PATCH 1/3] tests/vm: Set UseDNS=no in the sshd configuration Thomas Huth
2024-01-25 19:48 ` [PATCH 2/3] tests/vm/freebsd: Reload " Ilya Leoshkevich
2024-01-31 12:46   ` Thomas Huth
2024-01-25 19:48 ` [PATCH 3/3] meson: Disable CONFIG_NOTIFY1 on FreeBSD Ilya Leoshkevich
2024-01-31 12:50   ` Thomas Huth
2024-01-31 16:24   ` Philippe Mathieu-Daudé
2024-01-31 16:42     ` Daniel P. Berrangé
2024-02-05 15:23       ` Warner Losh
2024-02-05 15:31         ` Daniel P. Berrangé
2024-02-05 15:56           ` Ilya Leoshkevich
2024-02-05 16:02           ` Kyle Evans
2024-01-31 13:24 ` [PATCH 0/3] make vm-build-freebsd fixes Thomas Huth
2024-01-31 13:24   ` Ilya Leoshkevich

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