From 297e6e535d6117359ef24b091c35260fcf3b4ddd Mon Sep 17 00:00:00 2001
From: Guido Trotter <ultrotter@google.com>
Date: Fri, 4 Jun 2010 14:03:43 +0100
Subject: [PATCH] _ExecuteKVMRuntime: fix hv parameter fun
When executing the kvm runtime we were currently accessing a mix of the
parameters as configured currently on the instance and the ones it was
started with. We were doing it without a precise criteria, but quite by
chance we got it *almost* right. The only remaining issue was that when
ganeti was upgraded and some parameters were added, trying to access
them from the "old" ones caused a keyerror, since they weren't present
back when the instance was started.
To fix this:
- We fill the startup-time dict with any new parameter
- We provide a clear guideline on which version of the parameters to
access, and about the fact that new parameters must have an
instance-migration backwards compatible default
Signed-off-by: Guido Trotter <ultrotter@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>
---
lib/hypervisor/hv_kvm.py | 33 +++++++++++++++++++++++++--------
1 file changed, 25 insertions(+), 8 deletions(-)
diff --git a/lib/hypervisor/hv_kvm.py b/lib/hypervisor/hv_kvm.py
index c1b0710e4..81499b584 100644
--- a/lib/hypervisor/hv_kvm.py
+++ b/lib/hypervisor/hv_kvm.py
@@ -640,26 +640,40 @@ class KVMHypervisor(hv_base.BaseHypervisor):
@param incoming: (target_host_ip, port)
"""
- hvp = instance.hvparams
+ # Small _ExecuteKVMRuntime hv parameters programming howto:
+ # - conf_hvp contains the parameters as configured on ganeti. they might
+ # have changed since the instance started; only use them if the change
+ # won't affect the inside of the instance (which hasn't been rebooted).
+ # - up_hvp contains the parameters as they were when the instance was
+ # started, plus any new parameter which has been added between ganeti
+ # versions: it is paramount that those default to a value which won't
+ # affect the inside of the instance as well.
+ conf_hvp = instance.hvparams
name = instance.name
self._CheckDown(name)
temp_files = []
- kvm_cmd, kvm_nics, hvparams = kvm_runtime
+ kvm_cmd, kvm_nics, up_hvp = kvm_runtime
+ up_hvp = objects.FillDict(conf_hvp, up_hvp)
- security_model = hvp[constants.HV_SECURITY_MODEL]
+ # We know it's safe to run as a different user upon migration, so we'll use
+ # the latest conf, from conf_hvp.
+ security_model = conf_hvp[constants.HV_SECURITY_MODEL]
if security_model == constants.HT_SM_USER:
- kvm_cmd.extend(["-runas", hvp[constants.HV_SECURITY_DOMAIN]])
+ kvm_cmd.extend(["-runas", conf_hvp[constants.HV_SECURITY_DOMAIN]])
+ # We have reasons to believe changing something like the nic driver/type
+ # upon migration won't exactly fly with the instance kernel, so for nic
+ # related parameters we'll use up_hvp
if not kvm_nics:
kvm_cmd.extend(["-net", "none"])
else:
tap_extra = ""
- nic_type = hvparams[constants.HV_NIC_TYPE]
+ nic_type = up_hvp[constants.HV_NIC_TYPE]
if nic_type == constants.HT_NIC_PARAVIRTUAL:
nic_model = "model=virtio"
- if hvparams[constants.HV_VHOST_NET]:
+ if up_hvp[constants.HV_VHOST_NET]:
tap_extra = ",vhost=on"
else:
nic_model = "model=%s" % nic_type
@@ -676,7 +690,10 @@ class KVMHypervisor(hv_base.BaseHypervisor):
target, port = incoming
kvm_cmd.extend(['-incoming', 'tcp:%s:%s' % (target, port)])
- vnc_pwd_file = hvp[constants.HV_VNC_PASSWORD_FILE]
+ # Changing the vnc password doesn't bother the guest that much. At most it
+ # will surprise people who connect to it. Whether positively or negatively
+ # it's debatable.
+ vnc_pwd_file = conf_hvp[constants.HV_VNC_PASSWORD_FILE]
vnc_pwd = None
if vnc_pwd_file:
try:
@@ -685,7 +702,7 @@ class KVMHypervisor(hv_base.BaseHypervisor):
raise errors.HypervisorError("Failed to open VNC password file %s: %s"
% (vnc_pwd_file, err))
- if hvp[constants.HV_KVM_USE_CHROOT]:
+ if conf_hvp[constants.HV_KVM_USE_CHROOT]:
utils.EnsureDirs([(self._InstanceChrootDir(name),
constants.SECURE_DIR_MODE)])
--
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