Dynamic load balancing in a pull scheme

var col = {
  'c1' : {
    'wrk' : {
      'w1' : {
        'hst' : {
          'h1' : 5
        , 'h2' : 1
        , 'h3' : 1
        }
      , 'cpu' : 80.0
      }
    , 'w2' : {
        'hst' : {
          'h4' : 1
        , 'h5' : 1
        , 'h6' : 1
        }
      , 'cpu' : 20.0
      }
    }
  }
, 'c2' : {
    'wrk' : {
      'w1' : {
        'hst' : {
          'h7' : 1
        , 'h8' : 2
        }
      , 'cpu' : 100.0
      }
    , 'w2' : {
        'hst' : {
          'h9' : 1
        , 'hA' : 1
        , 'hB' : 1
        }
      , 'cpu' : 50.0
      }
    }
  }
};

//       ""
let $iv = (obj, fn) => Object.values(obj).forEach(fn);
let $mv = (obj, fn) => Object.values(obj).map(fn);

// initial reparse
for (const [cid, c] of Object.entries(col)) {
  $iv(c.wrk, w => {
    w.hst = Object.keys(w.hst).reduce((rv, hid) => {
      if (typeof w.hst[hid] == 'object') {
        rv[hid] = w.hst[hid];
        return rv;
      }
      //     ,   
      if (w.hst[hid]) {
        rv[hid] = {'qty' : w.hst[hid]};
      }
      return rv;
    }, {});
  });
  c.wrk = Object.keys(c.wrk).reduce((rv, wid) => {
    // ID    -
    rv[cid + ':' + wid] = c.wrk[wid];
    return rv;
  }, {});
}

//  
let S = col => {
  let wsum = 0
    , wavg = 0
    , wqty = 0
    , csum = 0
    , cavg = 0
    , cqty = 0;

  $iv(col, c => {
    $iv(c.wrk, w => {
      wsum += w.cpu;
      wqty++;
    });
    csum += c.cpu;
    cqty++;
  });
  wavg = wsum/wqty;
  wsum = 0;
  cavg = csum/cqty;
  csum = 0;
  $iv(col, c => {
    $iv(c.wrk, w => {
      wsum += (w.cpu - wavg) ** 2;
    });
    csum += (c.cpu - cavg) ** 2;
  });
  return [Math.sqrt(wsum/wqty), Math.sqrt(csum/cqty)];
};

// -
let distS = S => Math.sqrt(S[0] ** 2 + S[1] ** 2);

//      
let iterReOrder = col => {
  let qty = 0
    , max = 0;

  $iv(col, c => {
    c.qty = 0;
    c.cpu = 0;
    $iv(c.wrk, w => {
      w.qty = 0;
      $iv(w.hst, h => {
        w.qty += h.qty;
      });
      w.max = w.qty * (100/w.cpu);
      c.qty += w.qty;
      c.cpu += w.cpu;
    });
    c.cpu = c.cpu/Object.keys(c.wrk).length;
    c.max = c.qty * (100/c.cpu);
    qty += c.qty;
    max += c.max;
  });

  $iv(col, c => {
    c.nrm = c.max/max;
    $iv(c.wrk, w => {
      $iv(w.hst, h => {
        h.cpu = h.qty/w.qty * w.cpu;
        h.nrm = h.cpu * c.nrm;
      });
    });
  });

  // ""  
  console.log(S(col), distS(S(col)));

  //     
  let wrk = {};
  let hst = {};
  for (const [cid, c] of Object.entries(col)) {
    for (const [wid, w] of Object.entries(c.wrk)) {
      wrk[wid] = {
        wid
      , cid
      , 'wrk' : w
      , 'col' : c
      };
      for (const [hid, h] of Object.entries(w.hst)) {
        hst[hid] = {
          hid
        , wid
        , cid
        , 'hst' : h
        , 'wrk' : w
        , 'col' : c
        };
      }
    }
  }

  //      worker
  let move = (col, hid, wid) => {
    let w = wrk[wid]
      , h = hst[hid];

    let wsrc = col[h.cid].wrk[h.wid]
      , wdst = col[w.cid].wrk[w.wid];

    wsrc.cpu -= h.hst.cpu;
    wsrc.qty -= h.hst.qty;
    wdst.qty += h.hst.qty;
    //      ""   CPU
    if (h.cid != w.cid) {
      let csrc = col[h.cid]
        , cdst = col[w.cid];
      csrc.qty -= h.hst.qty;
      csrc.cpu -= h.hst.cpu/Object.keys(csrc.wrk).length;
      wsrc.hst[hid].cpu = h.hst.cpu * csrc.nrm/cdst.nrm;
      cdst.qty += h.hst.qty;
      cdst.cpu += h.hst.cpu/Object.keys(cdst.wrk).length;
    }
    wdst.cpu += wsrc.hst[hid].cpu;
    wdst.hst[hid] = wsrc.hst[hid];
    delete wsrc.hst[hid];
  };

  //       (host, worker)
  let moveCheck = (orig, hid, wid) => {
    let w = wrk[wid]
      , h = hst[hid];

    //    -   
    if (h.wid == w.wid) {
      return;
    }

    let col = JSON.parse(JSON.stringify(orig));
    move(col, hid, wid);

    return S(col);
  };

  //     (hsrc,hdst,%cpu)
  let checked = {};

  //     (  ->   )
  let moveRanker = col => {
    let currS = S(col);
    let order = [];

    for (hid in hst) {
      for (wid in wrk) {
        //          (   0.1%) ""    
        let widsrc = hst[hid].wid;
        let idx = widsrc + '|' + wid + '|' + hst[hid].hst.cpu.toFixed(1);
        if (idx in checked) {
          continue;
        }
        
        let _S = moveCheck(col, hid, wid);
        if (_S === undefined) {
          _S = currS;
        }
        checked[idx] = {
          hid
        , wid
        , S : _S
        };
        order.push(checked[idx]);
      }
    }
    order.sort((x, y) => distS(x.S) - distS(y.S));
    return order;
  };

  let currS = S(col);
  let order = moveRanker(col);

  let opt = order[0];
  console.log('best move', opt);

  //  
  if (distS(opt.S) < distS(currS)) {
    console.log('move!', opt.hid, opt.wid);
    move(col, opt.hid, opt.wid);
    console.log('after move', JSON.parse(JSON.stringify(col)));
    return true;
  }
  else {
    console.log('none!');
  }
  return false;
};

//   - 
while(iterReOrder(col));