mongodb java driver - com.mongodb.MongoException: can't find a master -


i trying connect remote mongodb. developed application local mongodb. deployed application dev , configured dev mongodb. getting following exception.

caused by: com.mongodb.mongoexception: can't find master     @ com.mongodb.dbtcpconnector.checkmaster(dbtcpconnector.java:509)     @ com.mongodb.dbtcpconnector.call(dbtcpconnector.java:266)     @ com.mongodb.dbapilayer$mycollection.__find(dbapilayer.java:289)     @ com.mongodb.dbapilayer$mycollection.__find(dbapilayer.java:274)     @ com.mongodb.dbcursor._check(dbcursor.java:368)     @ com.mongodb.dbcursor._hasnext(dbcursor.java:459)     @ com.mongodb.dbcursor.hasnext(dbcursor.java:484)

the funny thing can connect dev mongodb replica set server addresses local application, when try have application(deplyed dev) connect dev mongodb, see error above.

i wondering if there has faced same issue , resolved it.

this confounding aspect of mongodb has clashing principles of political science in voting policy.

here how happens.

  • a replica set exists; must have odd number of voting nodes.
  • the primary node fails because server / network goes down or brought down. other nodes may fail importantly...
  • an number of nodes remain no primary.
  • the remaining number of nodes cannot settle on primary , caught in political deadlock (aka hung parliament no majority).
    • a re-election occurs primary still down; deadlock. loop here.

one solution sway election assigning weight votes such candidates no longer equal. in mongo world, done assigning priority members.

priority comparisons priority setting affects elections. members prefer vote members highest priority value.

one entering mongo shell (on admin) , updating rs.conf

cfg = rs.conf() cfg.members[0].priority = 100 cfg.members[1].priority = 99 cfg.members[3].priority = 98 rs.reconfig(cfg)

under configuration, when primary member 0 fails member 1 voted primary.

here links:

http://docs.mongodb.org/manual/core/replica-set-elections/

http://docs.mongodb.org/manual/core/replica-set-architecture-four-members/

finally, situation common on cloud architecture techniques availability sets, scaling , down -- time,cpu,load or other metrics -- , should handled random or unfair discriminating policy default replica sets. without techniques primary on default replica set going deadlock @ point, making unavailable. significant failure in opinion.


Comments

Post a Comment

Popular posts from this blog

c# - DetailsView in ASP.Net - How to add another column on the side/add a control in each row? -

i have detailsview control on page used edit various fields of record, works in respect. i looking way add 1 column (and if works, why not more) right, absolutely read-only, show same fields of record comparison purposes. i aware there no obvious way such thing out of box detailsview . have looked other controls (transposed gridview , recommended formview , listview ), nothing satisfies. have special data binding setup using detailsview , can't out of without losing features. anyone on how "hack in" additional columns (for display only) on detailsview ? the solution have now, use second detailsview , visible set false in aspx. in code, make sure databind hidden detailsview hosts data third column first, initial detailsview named itemdetails . and in item created event, pass third column html rendering of hidden controls (in last code block) : protected void itemdetails_itemcreated(object sender, eventargs e) { if (dataite
Read more

javascript - firefox memory leak -

i have following script (i use raphaeljs also) draws circle, waits 1 second, draws circle again, etc (you can copy paste - functional, need include raphael raphaeljs.com): <div id="holder"> </div> <script src="raphael.js" type="text/javascript"></script> <script> var paper = raphael(10, 50, 320, 200); var rad = math.pi / 180; var finangle = 0; function sector(cx, cy, r, startangle, endangle, params) { var x1 = cx + r * math.cos(-startangle * rad), x2 = cx + r * math.cos(-endangle * rad), y1 = cy + r * math.sin(-startangle * rad), y2 = cy + r * math.sin(-endangle * rad); return ["m", cx, cy, "l", x1, y1, "a", r, r, 0, +(endangle - startangle > 180), 0, x2, y2]; } var path = sector(100,100,50,0,180); var arc = paper.path(path); function draw() { path = sector(100,100,50,0,finangle);
Read more

Trying to import CSV file to a SQL Server database using asp.net and c# - can't find what I'm missing -

i student , quite new programming, , given task using asp.net , c#, without being taught either. plan learn teach ourselves. the task stuck on making website import csv file sql server database of last year's room bookings around campus. the table has following columns: request_id; priority; module_id; day; start_time; length; park; students; room_code; status; semester_id; linked_request; week_1; week_2; week_3; week_4; week_5; week_6; week_7; week_8; week_9; week_10; week_11; week_12; week_13; week_14; week_15; ) in code, try make work 3 columns (request_id,priority,module) starters. when press import button, want read .csv file (with fixed name @ fixed directory) eg "1,2,3" - comma separating fields [delimiter] - , import sql server datab
Read more