#devstack

之前介紹過

在Google Cloud Platform(GCP)快速安裝Open edX線上教學平台(Native installation),

也提過

在Ubuntu 16.04 快速安裝Open edX線上教學平台(Native installation)

除了Native安裝以外,

還有專為開發用的Devstack版本,

今天就要來教大家

在Ubuntu16.04安裝Open edX 開發用devstack

Devstack是在開發設計的Docker容器中部署Open edX平台, 運行Open edX平台希望藉由此版本提早發現並修復系統配置問題, Devstack跟Native 版本不大一樣,

例如 在Devstack中禁用nginx和gunicorn, 改為使用Django的runserver代替, 原因無他,

它就是開發版本的Open edX,

Instance Resource Quota

IO limits

OS uses QEMU’s blkdeviotune underneath to apply i/o limits. Limits are setup at flavor level, altering them requires resizing an instance.

Setting up flavor with limits:

nova flavor-key <flavor name> set quota:disk_read_bytes_sec=<limit> nova flavor-key <flavor name> set quota:disk_write_bytes_sec=<limit>

CPU limits

Those are handled with CPU cgroup controller and applied at flavor level as well:

nova flavor-key <flavor name> set quota:cpu_quota=<limit> nova flavor-key <flavor name> set quota:cpu_period=<limit>

Bandwidth limits

Tc is used to control traffic shaping.

nova flavor-key <flavor name> set quota:vif_inbound_average=<limit> nova flavor-key <flavor name> set quota:vif_outbound_average=<limit>

Ref:. https://wiki.openstack.org/wiki/InstanceResourceQuota

Persisting DevStack’s ‘br-ex’ interface configuration across host OS reboots (on Ubuntu 18.04)

Stack.sh

Once stack.sh successfully deploys DevStack the ‘br-ex’ OVS bridge is assigned an IPv4 address of 172.24.4.1/24:

br-ex: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default qlen 1000 link/ether 46:98:c5:26:1d:49 brd ff:ff:ff:ff:ff:ff inet 172.24.4.1/24 brd 172.24.4.255 scope global br-ex   valid_lft forever preferred_lft forever

Also there is an iptables rule for floating IPs masking:

# /sbin/iptables -t nat -L POSTROUTING (...) MASQUERADE  all  --  172.24.4.0/24        anywhere

Once the host OS is rebooted all of the above is lost and OS instances are no longer reachable via floating IPs assigned to them.

Persisting the configuration

Create Netplan yaml file for br-ex interface:

/# cd /etc/netplan/ /etc/netplan# cat 99-br-ex.yaml network:    version: 2    renderer: networkd    ethernets:        br-ex:            addresses:                - 172.24.4.1/24

Test new settings:

/etc/netplan# netplan try (...) Configuration accepted.

Persist iptables rule: