94 lines
4.9 KiB
Markdown
94 lines
4.9 KiB
Markdown
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# NOTE
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## here is some thinking and notes in coding
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* path : scripts' path should be known by scripts to call/import other script -- use environment variables
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* FS_PREFIX : docklet filesystem path to put data
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* overlay : " modprobe overlay " to add overlay module
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* after reboot :
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* bridges lost -- it's ok, recreate it
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* loop device lost -- losetup /dev/loop0 BLOCK_FILE again, and lvm will get group and volume back automatically
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* lvm can do snapshot, image management can use lvm's snapshot -- No! lvm snapshot will use the capacity of LVM group.
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* cgroup memory control maybe not work. need run command below:
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echo 'GRUB_CMDLINE_LINUX="cgroup_enable=memory swapaccount=1"' >> /etc/default/grub && update-grub && reboot
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* debian don't support cpu.cfs_quota_us option in cgroup. it needs to recompile linux kernel with CONFIG_CFS_BANDWIDTH option
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* ip can add bridge/link/GRE, maybe we should test whether ip can replace of ovs-vsctl and brctl. ( see "man ip-link" )
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* lxc.mount.entry :
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* do not use relevant path. use absolute path, like :
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lxc.mount.entry = /root/from-dir /root/rootfs/to-dir none bind 0 0 # lxc.rootfs = /root/rootfs
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if use relevant paht, container path will be mounted on /usr/lib/x86_64..../ , a not existed path
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* path of host and container should both exist. if not exist in container, it will be mounted on /usr/lib/x86_64....
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* if path in container not exists, you can use option : create=dir/file, like :
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lxc.mount.entry = /root/from-dir /root/rootfs/to-dir none bind,create=dir 0 0 # lxc.rootfs = /root/rootfs
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* lxc.mount.entry : bind and rbind ( see "man mount" )
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* bind means mount a part of filesystem on somewhere else of this filesystem
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* but bind only attachs a single filesystem. That means the submount of source directory of mount may disappear in target directory.
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* if you want to make submount work, use rbind option.
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rbind will make entire file hierarchy including submounts mounted on another place.
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* NOW, we use bind in container.sh. maybe it need rbind if FS_PREFIX/global/users/$USERNAME/nfs is under glusterfs mountpoint
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* rpc server maybe not security. anyone can call rpc method if he knows ip address.
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* maybe we can use "transport" option of xmlrpc.client.ServerProxy(uri, transport="http://user:pass@host:port/path") and SimpleXMLRPCRequestHandler of xmlrpc.server.SimpleXMLRPCServer(addr, requestHandler=..) to parse the rpc request and authenticate the request
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xmlrpc.client.ServerProxy can also support https request, it is also a security method
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* If we use rpc with authentication, maybe we can use http server and http request to replace rpc
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* frontend and backend
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arch:
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+-----------------+
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Web -- Flask --HttpRest Core |
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+-----------------+
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Now, HttpRest and Core work as backend
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Web and Flask work as frontend
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all modules are in backend
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Flask just dispatch urls and render web pages
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(Maybe Flask can be merged in Core and works as http server)
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(Then Flask needs to render pages, parse urls, response requests, ...)
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(It maybe not fine)
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* httprest.py :
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httphandler needs to call vclustermgr/nodemgr/... to handler request
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we need to call these classes in httphandler
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Way-1: init/new these classes in httphandler init function (httphandler need to init parent class) -- wrong : httpserver will create a new httphandler instance for every http request ( see /usr/lib/python3.4/socketserver.py )
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Way-2: use global varibles -- Now this way
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* in shell, run python script or other not built-in command, the command will run in new process and new process group ( see csapp shell lab )
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so, the environment variables set in shell can not be see in python/...
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but command like below can work :
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A=ab B=ba ./python.py
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* maybe we need to parse argvs in python
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some module to parse argvs : sys.argv, optparse, getopt, argparse
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* in shell, { command; } means run command in current shell, ";" is necessary
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( command; ) means run command in sub shell
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* function in registered in rpc server must have return.
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without return, the rpc client will raise an exception
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* ** NEED TO BE FIX **
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we add a prefix in etcdlib
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so when we getkey, key may be a absolute path from base url
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when we setkey use the key we get, etcdlib will append the absolute path to prefix, it will wrong
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* overlay : upperdir and workdir must in the same mount filesystem.
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that means we should mount LV first and then mkdir upperdir and workdir in the LV mountpoint
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* when use 'worker.py > log' to redirect output of python script, it will empty output of log.
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because python interpreter will use buffer to collect output.
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we can use ways below to fix this problem:
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stdbuf -o 0 worker.py > log # but it fail in my try. don't know why
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python3 -u worker.py > log # recommended, -u option of python3
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print('output', flush=True) # flush option of print
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sys.stdout.flush() # flush by hand
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* CPU QUOTA should not be too small. too small it will work so slowly
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