最近的OpenStack nova版本增加了对实时实例的支持，即提供实时应用所需的确定性和性能保证的实例。这项工作在OpenStack Ocata发行版中最终标记为完成。
HOST BIOS配置
最重要的步骤是：
- 禁用电源管理，包括CPU睡眠状态
- 禁用超线程或与逻辑处理器相关的任何选项
这些是benchmarking中使用的标准步骤，否则都可能导致非确定性行为。
HOST配置
安装 CentOS 7
添加 RT repo
代码语言：javascript复制$ echo << EOF > /etc/yum.repos.d/CentOS-RT.repo
# CentOS-RT.repo
#
# The Real Time (RT) repository.
#
[rt]
name=CentOS-$releasever - rt
baseurl=http://mirror.centos.org/centos/$releasever/rt/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=1
EOF
$ sudo yum update -y
$ wget http://linuxsoft.cern.ch/cern/centos/7/rt/CentOS-RT.repo /etc/yum.repos.d/CentOS-RT.repo
$ wget http://linuxsoft.cern.ch/cern/centos/7/os/x86_64/RPM-GPG-KEY-cern /etc/pki/rpm-gpg/RPM-GPG-KEY-cern
$ sudo yum groupinstall RT安装dependencies
代码语言：javascript复制$ yum remove tuned
$ yum install -y tuned-2.7.1-5.el7
$ yum install -y centos-release-qemu-ev
$ yum install -y tuned-profiles-realtime tuned-profiles-nfv
$ yum install -y kernel-rt.x86_64 kernel-rt-kvm.x86_64配置realtime profile
代码语言：javascript复制$ lscpu | grep ^NUMA
NUMA node(s): 2
NUMA node0 CPU(s): 0,2,4,6,8,10
NUMA node1 CPU(s): 1,3,5,7,9,11
$ echo "isolated_cores=4-11" >> /etc/tuned/realtime-virtual-host-variables.confload realtime profile
代码语言：javascript复制$ systemctl enable tuned
$ systemctl start tuned
$ tuned-adm profile realtime-virtual-host
$ grep tuned_params= /boot/grub2/grub.cfg
set tuned_params="isolcpus=4-11 nohz=on nohz_full=4-11 intel_pstate=disable nosoftlockup"配置大页内存
添加 default_hugepagesz=1G 到 /etc/default/grub
代码语言：javascript复制$ grub2-mkconfig -o /boot/grub2/grub.cfg
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-3.10.0-327.13.1.el7.x86_64
done
$ echo 4 > /sys/devices/system/node/node0/hugepages/hugepages-1048576kB/nr_hugepages
$ echo 4 > /sys/devices/system/node/node1/hugepages/hugepages-1048576kB/nr_hugepages
$ cat << EOF > /usr/lib/systemd/system/hugetlb-gigantic-pages.service
[Unit]
Description=HugeTLB Gigantic Pages Reservation
DefaultDependencies=no
Before=dev-hugepages.mount
ConditionPathExists=/sys/devices/system/node
ConditionKernelCommandLine=hugepagesz=1G
[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/usr/lib/systemd/hugetlb-reserve-pages
[Install]
WantedBy=sysinit.target
EOF
$ cat << EOF > /usr/lib/systemd/hugetlb-reserve-pages
#!/bin/bash
nodes_path=/sys/devices/system/node/
if [ ! -d $nodes_path ]; then
echo "ERROR: $nodes_path does not exist"
exit 1
fi
reserve_pages()
{
echo $1 > $nodes_path/$2/hugepages/hugepages-1048576kB/nr_hugepages
}
reserve_pages 4 node0
reserve_pages 4 node1
EOF
$ chmod x /usr/lib/systemd/hugetlb-reserve-pages
$ systemctl enable hugetlb-gigantic-pagesreboot host
Verify
代码语言：javascript复制$ tuned-adm active
Current active profile: realtime-virtual-host
$ cat /proc/cmdline
BOOT_IMAGE=/vmlinuz-3.10.0-327.18.2.rt56.223.el7_2.x86_64 root=/dev/mapper/rhel_virtlab502-root ro crashkernel=auto rd.lvm.lv=rhel_virtlab502/root rd.lvm.lv=rhel_virtlab502/swap console=ttyS1,115200 default_hugepagesz=1G isolcpus=3,5,7 nohz=on nohz_full=3,5,7 intel_pstate=disable nosoftlockup
$ cat /sys/module/kvm/parameters/lapic_timer_advance_ns
1000 # this should be a non-0 value
$ cat /sys/devices/system/node/node0/hugepages/hugepages-1048576kB/nr_hugepages
4
$ cat /sys/devices/system/node/node1/hugepages/hugepages-1048576kB/nr_hugepages
4
$ yum install -y rt-tests
$ hwlatdetect
hwlatdetect: test duration 120 seconds
parameters:
Latency threshold: 10us
Sample window: 1000000us
Sample width: 500000us
Non-sampling period: 500000us
Output File: None
Starting test
test finished
Max Latency: 0us
Samples recorded: 0
Samples exceeding threshold: 0
$ yum install rteval
$ rteval --onlyload --duration=4h --verboseGuest配置
eneble rt repo
代码语言：javascript复制$ echo << EOF > /etc/yum.repos.d/CentOS-RT.repo
# CentOS-RT.repo
#
# The Real Time (RT) repository.
#
[rt]
name=CentOS-$releasever - rt
baseurl=http://mirror.centos.org/centos/$releasever/rt/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=1
EOF
$ sudo yum update -y安装dependencies
代码语言：javascript复制$ yum remove tuned
$ yum install -y tuned-2.7.1-5.el7
$ yum install -y centos-release-qemu-ev
$ yum install -y tuned-profiles-realtime tuned-profiles-nfv
$ yum install -y kernel-rt.x86_64Configure the realtime profile
代码语言：javascript复制$ echo "isolated_cores=2,3" >> /etc/tuned/realtime-virtual-guest-variables.confLoad the realtime profile
代码语言：javascript复制$ systemctl enable tuned
$ systemctl start tuned
$ tuned-adm profile realtime-virtual-guest
$ grep tuned_params= /boot/grub2/grub.cfg set
tuned_params="isolcpus=2,3 nohz=on nohz_full=2,3 rcu_nocbs=2,3 intel_pstate=disable nosoftlockup"配置大页内存
添加 default_hugepagesz=1G 到 /etc/default/grub
代码语言：javascript复制$ grub2-mkconfig -o /boot/grub2/grub.cfg
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-3.10.0-327.13.1.el7.x86_64
done安装testing dependencies
代码语言：javascript复制$ yum install -y epel-release
$ yum install -y rt-tests stressReboot the guest to apply changes
Verify the changes have been applied
代码语言：javascript复制$ tuned-adm active
Current active profile: realtime-virtual-guest
$ uname -a
Linux guest.localdomain 3.10.0-693.2.2.rt56.623.el7.x86_64 #1 SMP PREEMPT RT Sun Jan 01 00:00:00 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
$ cat /proc/cmdline
BOOT_IMAGE=/vmlinuz-3.10.0-693.2.2.rt56.623.el7.x86_64 root=/dev/mapper/centos-root ro rd.lvm.lv=centos/root rd.lvm.lv=centos/swap console=ttyS0,115200n8 default_hugepagesz=1G isolcpus=2,3 nohz=on nohz_full=2,3 rcu_nocbs=2,3 intel_pstate=disable nosoftlockupInstall OpenStack-specific dependencies
代码语言：javascript复制$ yum install -y acpid
$ systemctl enable acpid
$ yum install -y cloud-init cloud-utils-growpart
$ echo "NOZEROCONF=yes" >> /etc/sysconfig/network
$ poweroffClean up the image
代码语言：javascript复制centos7: vm name
$ sudo virt-sysprep -d centos7
$ sudo virsh undefine centos7
$ sudo qemu-img convert -O qcow2 -c centos7.qcow2 centos7-small.qcow2Nova 配置
首先安装openstack
Configure flavor
代码语言：javascript复制$ openstack flavor create --vcpus 4 --ram 4096 --disk 20 rt1.small
$ openstack flavor set rt1.small
--property 'hw:cpu_policy=dedicated'
--property 'hw:cpu_realtime=yes'
--property 'hw:cpu_realtime_mask=^0-1'
--property 'hw:mem_page_size=1GB'
By way of an explanation, these various properties correspond to the following.
hw:cpu_policy=dedicated
This indicates that instances must have exclusive pCPUs assigned to them.
hw:cpu_realtime=yes
This indicates that instances will have a real-time policy.
hw:cpu_realtime_mask="^0-1"
This indicates that all instance vCPUs except vCPUs 0 and 1 will have a real-time policy.
hw:mem_page_size=1GB
This indicates that instances will have a sole 1 GB huge page assigned to them.Configure image
代码语言：javascript复制$ openstack image create --disk-format qcow2 --container-format bare
--public --file ./centos-small.qcow2 centos-rtConfigure security groups and keypairs
代码语言：javascript复制$ echo OS_PROJECT_NAME
demo
$ openstack project list | grep -w demo
| f5a2496e6edf4ef4b5ffe62b01a8bf4b | demo |
$ openstack security group list | grep -w f5a2496e6edf4ef4b5ffe62b01a8bf4b
| 466ffc5e-114d-43a4-8854-db490c6b4571 | default | Default security group | f5a2496e6edf4ef4b5ffe62b01a8bf4b |
$ openstack security group rule create --proto icmp
466ffc5e-114d-43a4-8854-db490c6b4571
$ openstack security group rule create --proto tcp --dst-port 22
466ffc5e-114d-43a4-8854-db490c6b4571
In addition, we want to create a keypair so we can ssh into the instance.
$ openstack keypair create --public-key .ssh/id_rsa.pub default-key测试
代码语言：javascript复制$ openstack server create --flavor rt1.small --image centos-rt
--key-name default-key rt-server若报以下错误：Could not access KVM kernel module: Permission denied failed to initialize KVM: Permission denied
代码语言：javascript复制$ sudo rmmod kvm_intel
$ sudo rmmod kvm
$ sudo modprobe kvm
$ sudo modprobe kvm_intelssh to guest
代码语言：javascript复制$ openstack server ssh rt-server --login centosRun cyclictest to confirm expected latencies
代码语言：javascript复制$ taskset -c 2 stress --cpu 4
$ taskset -c 2 cyclictest -m -n -q -p95 -D 24h -h100 -i 200 > cyclictest.out
