On Sat, Nov 28, 2015 at 11:55 PM, Imesh Gunaratne <im...@apache.org> wrote:
> > > On Tue, Nov 24, 2015 at 12:58 PM, Sajith Kariyawasam <saj...@wso2.com> > wrote: >> >> >> There are two aspects in here as I see. >> 1) Applying patches to already running server and restart. >> 2) Applying patches to a 'fresh' server and start >> >> It would have been ideal if we can achieve both scenarios above, but yes, >> with the points you have mentioned (1) is not possible. I remember we had a >> discussion in past regarding this, >> did we finalized it?. So, if there is a running cluster (say,100 nodes) >> and if we need to apply a patch, approach would be to spawn up 'new' >> instances with the patches? >> >> Yes, currently we might need to do this because, if we apply a patch in > an active instance and restart the server. During that period it will > receive requests via the load balancer and those will fail. Few months back > Shaheed proposed a software update management feature to handle this logic. > > >> Even in that scenario, there is no easy way to track the changes being >> done to the originally released binary, since the current approach is to >> replace the old files with patched files. >> The model I was thinking is to implement a model where PCA always keep >> the original files (backed up) and read the latest files (from a patch >> location), which is the exact way of Carbon >> patch model. >> >> Right, I think this is a good approach. Can you please explain it using > an example? > > I have attached a sample directory structure. There will be a separate directory named "patches", into which the patches need to be copied. Say we have patched "agentgithandler.py" in patch0500 and its copied in patches directory as shown. When the agent starts up it checks whether there are any "patchxxxx" directories, and if so it backs up the original file(s) into patch0000, and replace original file with the patched file. If the patch folder is removed we need to restore the original file, in order to cater for that, the logic should be, at the startup agent checks whether there are any files in patch0000 directory (which means a patch is already applied) and search for that file in patchxxxx directories, if not found it compares the md5sum with the file in the original location. If it doesn't match, it will replace with the file in patch0000. Those logic needs to be written in python code and to be executed before starting any of the agent related code. I will try to send a PR soon so that it will be much clear about the process, and we can review it and do any modifications needed. > Thanks > > >> Can you please explain the patching process you are proposing? >>> >>> Thanks >>> >>> On Wed, Nov 11, 2015 at 6:07 PM, Sajith Kariyawasam <saj...@wso2.com> >>> wrote: >>> >>>> Hi Devs, >>>> >>>> At the moment Python Cartridge Agent (PCA) doesn't have a convenient >>>> way of applying patches. >>>> If there is an issue identified and fixed, in order to apply the fix to >>>> a running system that particular file(s) has to be replaced in the running >>>> system, >>>> and there is no easy way to revert the patch is there is any issue >>>> found later. >>>> Also, there is no way of tracking the list of patches applied. >>>> >>>> I would like to suggest to implement a patching model for PCA, similar >>>> to that we have in Stratos core, which is based on carbon [1] >>>> WDYT ? >>>> >>>> [1] >>>> https://docs.wso2.com/display/Carbon420/WSO2+Patch+Application+Process >>>> >>>> Thanks, >>>> Sajith >>>> >>>> -- >>>> Sajith Kariyawasam >>>> *Committer and PMC member, Apache Stratos, * >>>> *WSO2 Inc.; http://wso2.com <http://wso2.com>* >>>> *Mobile: 0772269575 <0772269575>* >>>> >>> >>> >>> >>> -- >>> Imesh Gunaratne >>> >>> Senior Technical Lead, WSO2 >>> Committer & PMC Member, Apache Stratos >>> >> >> >> >> -- >> Sajith Kariyawasam >> *Committer and PMC member, Apache Stratos, * >> *WSO2 Inc.; http://wso2.com <http://wso2.com>* >> *Mobile: 0772269575 <0772269575>* >> > > > > -- > Imesh Gunaratne > > Senior Technical Lead, WSO2 > Committer & PMC Member, Apache Stratos > -- Sajith Kariyawasam *Committer and PMC member, Apache Stratos, * *WSO2 Inc.; http://wso2.com <http://wso2.com>* *Mobile: 0772269575*
