Files
tromcho.net/mon/lp-optimizer.js
T
Vitaliy Filippov 4a2dcf7b6b Update the license to VNPL 1.1
VNPL 1.1 is slightly reworded to make it clear that proprietary software
interacting with Vitastor and providing some kind of service to end users isn't
a "Proxy Program" if it's not specially designed to be used with Vitastor.

For example, Windows OS running in a virtual machine stored in a Vitastor
cluster clearly isn't.
2021-02-25 23:55:33 +03:00

712 lines
22 KiB
JavaScript

// Copyright (c) Vitaliy Filippov, 2019+
// License: VNPL-1.1 (see README.md for details)
// Data distribution optimizer using linear programming (lp_solve)
const child_process = require('child_process');
const NO_OSD = 'Z';
async function lp_solve(text)
{
const cp = child_process.spawn('lp_solve');
let stdout = '', stderr = '', finish_cb;
cp.stdout.on('data', buf => stdout += buf.toString());
cp.stderr.on('data', buf => stderr += buf.toString());
cp.on('exit', () => finish_cb && finish_cb());
cp.stdin.write(text);
cp.stdin.end();
if (cp.exitCode == null)
{
await new Promise(ok => finish_cb = ok);
}
if (!stdout.trim())
{
return null;
}
let score = 0;
let vars = {};
for (const line of stdout.split(/\n/))
{
let m = /^(^Value of objective function: (-?[\d\.]+)|Actual values of the variables:)\s*$/.exec(line);
if (m)
{
if (m[2])
{
score = m[2];
}
continue;
}
else if (/This problem is (infeasible|unbounded)/.exec(line))
{
return null;
}
let [ k, v ] = line.trim().split(/\s+/, 2);
if (v)
{
vars[k] = v;
}
}
return { score, vars };
}
async function optimize_initial({ osd_tree, pg_count, pg_size = 3, pg_minsize = 2, max_combinations = 10000, parity_space = 1 })
{
if (!pg_count || !osd_tree)
{
return null;
}
const all_weights = Object.assign({}, ...Object.values(osd_tree));
const total_weight = Object.values(all_weights).reduce((a, c) => Number(a) + Number(c), 0);
const all_pgs = Object.values(random_combinations(osd_tree, pg_size, max_combinations, parity_space > 1));
const pg_per_osd = {};
for (const pg of all_pgs)
{
for (let i = 0; i < pg.length; i++)
{
const osd = pg[i];
pg_per_osd[osd] = pg_per_osd[osd] || [];
pg_per_osd[osd].push((i >= pg_minsize ? parity_space+'*' : '')+"pg_"+pg.join("_"));
}
}
const pg_effsize = Math.min(pg_minsize, Object.keys(osd_tree).length)
+ Math.max(0, Math.min(pg_size, Object.keys(osd_tree).length) - pg_minsize) * parity_space;
let lp = '';
lp += "max: "+all_pgs.map(pg => 'pg_'+pg.join('_')).join(' + ')+";\n";
for (const osd in pg_per_osd)
{
if (osd !== NO_OSD)
{
let osd_pg_count = all_weights[osd]/total_weight*pg_effsize*pg_count;
lp += pg_per_osd[osd].join(' + ')+' <= '+osd_pg_count+';\n';
}
}
for (const pg of all_pgs)
{
lp += 'pg_'+pg.join('_')+" >= 0;\n";
}
lp += "sec "+all_pgs.map(pg => 'pg_'+pg.join('_')).join(', ')+";\n";
const lp_result = await lp_solve(lp);
if (!lp_result)
{
console.log(lp);
throw new Error('Problem is infeasible or unbounded - is it a bug?');
}
const int_pgs = make_int_pgs(lp_result.vars, pg_count);
const eff = pg_list_space_efficiency(int_pgs, all_weights, pg_minsize, parity_space);
const res = {
score: lp_result.score,
weights: lp_result.vars,
int_pgs,
space: eff * pg_effsize,
total_space: total_weight,
};
return res;
}
function make_int_pgs(weights, pg_count)
{
const total_weight = Object.values(weights).reduce((a, c) => Number(a) + Number(c), 0);
let int_pgs = [];
let pg_left = pg_count;
let weight_left = total_weight;
for (const pg_name in weights)
{
let n = Math.round(weights[pg_name] / weight_left * pg_left);
for (let i = 0; i < n; i++)
{
int_pgs.push(pg_name.substr(3).split('_'));
}
weight_left -= weights[pg_name];
pg_left -= n;
}
return int_pgs;
}
function calc_intersect_weights(pg_size, pg_count, prev_weights, all_pgs)
{
const move_weights = {};
if ((1 << pg_size) < pg_count)
{
const intersect = {};
for (const pg_name in prev_weights)
{
const pg = pg_name.substr(3).split(/_/);
for (let omit = 1; omit < (1 << pg_size); omit++)
{
let pg_omit = [ ...pg ];
let intersect_count = pg_size;
for (let i = 0; i < pg_size; i++)
{
if (omit & (1 << i))
{
pg_omit[i] = '';
intersect_count--;
}
}
pg_omit = pg_omit.join(':');
intersect[pg_omit] = Math.max(intersect[pg_omit] || 0, intersect_count);
}
}
for (const pg of all_pgs)
{
let max_int = 0;
for (let omit = 1; omit < (1 << pg_size); omit++)
{
let pg_omit = [ ...pg ];
for (let i = 0; i < pg_size; i++)
{
if (omit & (1 << i))
{
pg_omit[i] = '';
}
}
pg_omit = pg_omit.join(':');
max_int = Math.max(max_int, intersect[pg_omit] || 0);
}
move_weights['pg_'+pg.join('_')] = pg_size-max_int;
}
}
else
{
const prev_pg_hashed = Object.keys(prev_weights).map(pg_name => pg_name.substr(3).split(/_/).reduce((a, c) => { a[c] = 1; return a; }, {}));
for (const pg of all_pgs)
{
if (!prev_weights['pg_'+pg.join('_')])
{
let max_int = 0;
for (const prev_hash in prev_pg_hashed)
{
const intersect_count = pg.reduce((a, osd) => a + (prev_hash[osd] ? 1 : 0), 0);
if (max_int < intersect_count)
{
max_int = intersect_count;
if (max_int >= pg_size)
{
break;
}
}
}
move_weights['pg_'+pg.join('_')] = pg_size-max_int;
}
}
}
return move_weights;
}
function add_valid_previous(osd_tree, prev_weights, all_pgs)
{
// Add previous combinations that are still valid
const hosts = Object.keys(osd_tree).sort();
const host_per_osd = {};
for (const host in osd_tree)
{
for (const osd in osd_tree[host])
{
host_per_osd[osd] = host;
}
}
skip_pg: for (const pg_name in prev_weights)
{
const seen_hosts = {};
const pg = pg_name.substr(3).split(/_/);
for (const osd of pg)
{
if (!host_per_osd[osd] || seen_hosts[host_per_osd[osd]])
{
continue skip_pg;
}
seen_hosts[host_per_osd[osd]] = true;
}
if (!all_pgs[pg_name])
{
all_pgs[pg_name] = pg;
}
}
}
// Try to minimize data movement
async function optimize_change({ prev_pgs: prev_int_pgs, osd_tree, pg_size = 3, pg_minsize = 2, max_combinations = 10000, parity_space = 1 })
{
if (!osd_tree)
{
return null;
}
const pg_effsize = Math.min(pg_minsize, Object.keys(osd_tree).length)
+ Math.max(0, Math.min(pg_size, Object.keys(osd_tree).length) - pg_minsize) * parity_space;
const pg_count = prev_int_pgs.length;
const prev_weights = {};
const prev_pg_per_osd = {};
for (const pg of prev_int_pgs)
{
const pg_name = 'pg_'+pg.join('_');
prev_weights[pg_name] = (prev_weights[pg_name]||0) + 1;
for (let i = 0; i < pg.length; i++)
{
const osd = pg[i];
prev_pg_per_osd[osd] = prev_pg_per_osd[osd] || [];
prev_pg_per_osd[osd].push([ pg_name, (i >= pg_minsize ? parity_space : 1) ]);
}
}
// Get all combinations
let all_pgs = random_combinations(osd_tree, pg_size, max_combinations, parity_space > 1);
add_valid_previous(osd_tree, prev_weights, all_pgs);
all_pgs = Object.values(all_pgs);
const pg_per_osd = {};
for (const pg of all_pgs)
{
const pg_name = 'pg_'+pg.join('_');
for (let i = 0; i < pg.length; i++)
{
const osd = pg[i];
pg_per_osd[osd] = pg_per_osd[osd] || [];
pg_per_osd[osd].push([ pg_name, (i >= pg_minsize ? parity_space : 1) ]);
}
}
// Penalize PGs based on their similarity to old PGs
const move_weights = calc_intersect_weights(pg_size, pg_count, prev_weights, all_pgs);
// Calculate total weight - old PG weights
const all_pg_names = all_pgs.map(pg => 'pg_'+pg.join('_'));
const all_pgs_hash = all_pg_names.reduce((a, c) => { a[c] = true; return a; }, {});
const all_weights = Object.assign({}, ...Object.values(osd_tree));
const total_weight = Object.values(all_weights).reduce((a, c) => Number(a) + Number(c), 0);
// Generate the LP problem
let lp = '';
lp += 'max: '+all_pg_names.map(pg_name => (
prev_weights[pg_name] ? `${pg_size+1}*add_${pg_name} - ${pg_size+1}*del_${pg_name}` : `${pg_size+1-move_weights[pg_name]}*${pg_name}`
)).join(' + ')+';\n';
for (const osd in pg_per_osd)
{
if (osd !== NO_OSD)
{
const osd_sum = (pg_per_osd[osd]||[]).map(([ pg_name, space ]) => (
prev_weights[pg_name] ? `${space} * add_${pg_name} - ${space} * del_${pg_name}` : `${space} * ${pg_name}`
)).join(' + ');
const rm_osd_pg_count = (prev_pg_per_osd[osd]||[])
.reduce((a, [ old_pg_name, space ]) => (a + (all_pgs_hash[old_pg_name] ? space : 0)), 0);
const osd_pg_count = all_weights[osd]*pg_effsize/total_weight*pg_count - rm_osd_pg_count;
lp += osd_sum + ' <= ' + osd_pg_count + ';\n';
}
}
let pg_vars = [];
for (const pg_name of all_pg_names)
{
if (prev_weights[pg_name])
{
pg_vars.push(`add_${pg_name}`, `del_${pg_name}`);
// Can't add or remove less than zero
lp += `add_${pg_name} >= 0;\n`;
lp += `del_${pg_name} >= 0;\n`;
// Can't remove more than the PG already has
lp += `add_${pg_name} - del_${pg_name} >= -${prev_weights[pg_name]};\n`;
}
else
{
pg_vars.push(pg_name);
lp += `${pg_name} >= 0;\n`;
}
}
lp += 'sec '+pg_vars.join(', ')+';\n';
// Solve it
const lp_result = await lp_solve(lp);
if (!lp_result)
{
console.log(lp);
throw new Error('Problem is infeasible or unbounded - is it a bug?');
}
// Generate the new distribution
const weights = { ...prev_weights };
for (const k in prev_weights)
{
if (!all_pgs_hash[k])
{
delete weights[k];
}
}
for (const k in lp_result.vars)
{
if (k.substr(0, 4) === 'add_')
{
weights[k.substr(4)] = (weights[k.substr(4)] || 0) + Number(lp_result.vars[k]);
}
else if (k.substr(0, 4) === 'del_')
{
weights[k.substr(4)] = (weights[k.substr(4)] || 0) - Number(lp_result.vars[k]);
}
else if (k.substr(0, 3) === 'pg_')
{
weights[k] = Number(lp_result.vars[k]);
}
}
for (const k in weights)
{
if (!weights[k])
{
delete weights[k];
}
}
const int_pgs = make_int_pgs(weights, pg_count);
// Align them with most similar previous PGs
const new_pgs = align_pgs(prev_int_pgs, int_pgs);
let differs = 0, osd_differs = 0;
for (let i = 0; i < pg_count; i++)
{
if (new_pgs[i].join('_') != prev_int_pgs[i].join('_'))
{
differs++;
}
for (let j = 0; j < pg_size; j++)
{
if (new_pgs[i][j] != prev_int_pgs[i][j])
{
osd_differs++;
}
}
}
return {
prev_pgs: prev_int_pgs,
score: lp_result.score,
weights,
int_pgs: new_pgs,
differs,
osd_differs,
space: pg_effsize * pg_list_space_efficiency(new_pgs, all_weights, pg_minsize, parity_space),
total_space: total_weight,
};
}
function print_change_stats(retval, detailed)
{
const new_pgs = retval.int_pgs;
const prev_int_pgs = retval.prev_pgs;
if (prev_int_pgs)
{
if (detailed)
{
for (let i = 0; i < new_pgs.length; i++)
{
if (new_pgs[i].join('_') != prev_int_pgs[i].join('_'))
{
console.log("pg "+i+": "+prev_int_pgs[i].join(' ')+" -> "+new_pgs[i].join(' '));
}
}
}
console.log(
"Data movement: "+retval.differs+" pgs, "+
retval.osd_differs+" pg*osds = "+Math.round(retval.osd_differs / prev_int_pgs.length / 3 * 10000)/100+" %"
);
}
console.log(
"Total space (raw): "+Math.round(retval.space*100)/100+" TB, space efficiency: "+
Math.round(retval.space/(retval.total_space||1)*10000)/100+" %"
);
}
function align_pgs(prev_int_pgs, int_pgs)
{
const aligned_pgs = [];
put_aligned_pgs(aligned_pgs, int_pgs, prev_int_pgs, (pg) => [ pg.join(':') ]);
put_aligned_pgs(aligned_pgs, int_pgs, prev_int_pgs, (pg) => [ pg[0]+'::'+pg[2], ':'+pg[1]+':'+pg[2], pg[0]+':'+pg[1]+':' ]);
put_aligned_pgs(aligned_pgs, int_pgs, prev_int_pgs, (pg) => [ pg[0]+'::', ':'+pg[1]+':', '::'+pg[2] ]);
const free_slots = prev_int_pgs.map((pg, i) => !aligned_pgs[i] ? i : null).filter(i => i != null);
for (const pg of int_pgs)
{
if (!free_slots.length)
{
throw new Error("Can't place unaligned PG");
}
aligned_pgs[free_slots.shift()] = pg;
}
return aligned_pgs;
}
function put_aligned_pgs(aligned_pgs, int_pgs, prev_int_pgs, keygen)
{
let prev_indexes = {};
for (let i = 0; i < prev_int_pgs.length; i++)
{
for (let k of keygen(prev_int_pgs[i]))
{
prev_indexes[k] = prev_indexes[k] || [];
prev_indexes[k].push(i);
}
}
PG: for (let i = int_pgs.length-1; i >= 0; i--)
{
let pg = int_pgs[i];
let keys = keygen(int_pgs[i]);
for (let k of keys)
{
while (prev_indexes[k] && prev_indexes[k].length)
{
let idx = prev_indexes[k].shift();
if (!aligned_pgs[idx])
{
aligned_pgs[idx] = pg;
int_pgs.splice(i, 1);
continue PG;
}
}
}
}
}
// Convert multi-level osd_tree = { level: number|string, id?: string, size?: number, children?: osd_tree }[]
// levels = { string: number }
// to a two-level osd_tree suitable for all_combinations()
function flatten_tree(osd_tree, levels, failure_domain_level, osd_level, domains = {}, i = { i: 1 })
{
osd_level = levels[osd_level] || osd_level;
failure_domain_level = levels[failure_domain_level] || failure_domain_level;
for (const node of osd_tree)
{
if ((levels[node.level] || node.level) < failure_domain_level)
{
flatten_tree(node.children||[], levels, failure_domain_level, osd_level, domains, i);
}
else
{
domains['dom'+(i.i++)] = extract_osds([ node ], levels, osd_level);
}
}
return domains;
}
function extract_osds(osd_tree, levels, osd_level, osds = {})
{
for (const node of osd_tree)
{
if ((levels[node.level] || node.level) >= osd_level)
{
osds[node.id] = node.size;
}
else
{
extract_osds(node.children||[], levels, osd_level, osds);
}
}
return osds;
}
// unordered = don't treat (x,y) and (y,x) as equal
function random_combinations(osd_tree, pg_size, count, unordered)
{
let seed = 0x5f020e43;
let rng = () =>
{
seed ^= seed << 13;
seed ^= seed >> 17;
seed ^= seed << 5;
return seed + 2147483648;
};
const hosts = Object.keys(osd_tree).sort();
const osds = Object.keys(osd_tree).reduce((a, c) => { a[c] = Object.keys(osd_tree[c]).sort(); return a; }, {});
const r = {};
// Generate random combinations including each OSD at least once
for (let h = 0; h < hosts.length; h++)
{
for (let o = 0; o < osds[hosts[h]].length; o++)
{
const pg = [ osds[hosts[h]][o] ];
const cur_hosts = [ ...hosts ];
cur_hosts.splice(h, 1);
for (let i = 1; i < pg_size && i < hosts.length; i++)
{
const next_host = rng() % cur_hosts.length;
const next_osd = rng() % osds[cur_hosts[next_host]].length;
pg.push(osds[cur_hosts[next_host]][next_osd]);
cur_hosts.splice(next_host, 1);
}
const cyclic_pgs = [ pg ];
if (unordered)
{
for (let i = 1; i < pg.size; i++)
{
cyclic_pgs.push([ ...pg.slice(i), ...pg.slice(0, i) ]);
}
}
for (const pg of cyclic_pgs)
{
while (pg.length < pg_size)
{
pg.push(NO_OSD);
}
r['pg_'+pg.join('_')] = pg;
}
}
}
// Generate purely random combinations
while (count > 0)
{
let host_idx = [];
const cur_hosts = [ ...hosts.map((h, i) => i) ];
const max_hosts = pg_size < hosts.length ? pg_size : hosts.length;
if (unordered)
{
for (let i = 0; i < max_hosts; i++)
{
const r = rng() % cur_hosts.length;
host_idx[i] = cur_hosts[r];
cur_hosts.splice(r, 1);
}
}
else
{
for (let i = 0; i < max_hosts; i++)
{
const r = rng() % (cur_hosts.length - (max_hosts - i - 1));
host_idx[i] = cur_hosts[r];
cur_hosts.splice(0, r+1);
}
}
let pg = host_idx.map(h => osds[hosts[h]][rng() % osds[hosts[h]].length]);
while (pg.length < pg_size)
{
pg.push(NO_OSD);
}
r['pg_'+pg.join('_')] = pg;
count--;
}
return r;
}
// Super-stupid algorithm. Given the current OSD tree, generate all possible OSD combinations
// osd_tree = { failure_domain1: { osd1: size1, ... }, ... }
// ordered = return combinations without duplicates having different order
function all_combinations(osd_tree, pg_size, ordered, count)
{
const hosts = Object.keys(osd_tree).sort();
const osds = Object.keys(osd_tree).reduce((a, c) => { a[c] = Object.keys(osd_tree[c]).sort(); return a; }, {});
while (hosts.length < pg_size)
{
osds[NO_OSD] = [ NO_OSD ];
hosts.push(NO_OSD);
}
let host_idx = [];
let osd_idx = [];
for (let i = 0; i < pg_size; i++)
{
host_idx.push(i);
osd_idx.push(0);
}
const r = [];
while (!count || count < 0 || r.length < count)
{
r.push(host_idx.map((hi, i) => osds[hosts[hi]][osd_idx[i]]));
let inc = pg_size-1;
while (inc >= 0)
{
osd_idx[inc]++;
if (osd_idx[inc] >= osds[hosts[host_idx[inc]]].length)
{
osd_idx[inc] = 0;
inc--;
}
else
{
break;
}
}
if (inc < 0)
{
// no osds left in the current host combination, select the next one
inc = pg_size-1;
same_again: while (inc >= 0)
{
host_idx[inc]++;
for (let prev_host = 0; prev_host < inc; prev_host++)
{
if (host_idx[prev_host] == host_idx[inc])
{
continue same_again;
}
}
if (host_idx[inc] < (ordered ? hosts.length-(pg_size-1-inc) : hosts.length))
{
while ((++inc) < pg_size)
{
host_idx[inc] = (ordered ? host_idx[inc-1]+1 : 0);
}
break;
}
else
{
inc--;
}
}
if (inc < 0)
{
break;
}
}
}
return r;
}
function pg_weights_space_efficiency(weights, pg_count, osd_sizes)
{
const per_osd = {};
for (const pg_name in weights)
{
for (const osd of pg_name.substr(3).split(/_/))
{
per_osd[osd] = (per_osd[osd]||0) + weights[pg_name];
}
}
return pg_per_osd_space_efficiency(per_osd, pg_count, osd_sizes);
}
function pg_list_space_efficiency(pgs, osd_sizes, pg_minsize, parity_space)
{
const per_osd = {};
for (const pg of pgs)
{
for (let i = 0; i < pg.length; i++)
{
const osd = pg[i];
per_osd[osd] = (per_osd[osd]||0) + (i >= pg_minsize ? (parity_space||1) : 1);
}
}
return pg_per_osd_space_efficiency(per_osd, pgs.length, osd_sizes);
}
function pg_per_osd_space_efficiency(per_osd, pg_count, osd_sizes)
{
// each PG gets randomly selected in 1/N cases
// & there are x PGs per OSD
// => an OSD is selected in x/N cases
// => total space * x/N <= OSD size
// => total space <= OSD size * N/x
let space;
for (let osd in per_osd)
{
if (osd in osd_sizes)
{
const space_estimate = osd_sizes[osd] * pg_count / per_osd[osd];
if (space == null || space > space_estimate)
{
space = space_estimate;
}
}
}
return space == null ? 0 : space;
}
module.exports = {
NO_OSD,
optimize_initial,
optimize_change,
print_change_stats,
pg_weights_space_efficiency,
pg_list_space_efficiency,
pg_per_osd_space_efficiency,
flatten_tree,
lp_solve,
make_int_pgs,
align_pgs,
random_combinations,
all_combinations,
};